diff --git a/modules/openapi-generator/src/main/resources/go/model_simple.mustache b/modules/openapi-generator/src/main/resources/go/model_simple.mustache
index dab19a27a0f..05e56b11b33 100644
--- a/modules/openapi-generator/src/main/resources/go/model_simple.mustache
+++ b/modules/openapi-generator/src/main/resources/go/model_simple.mustache
@@ -125,7 +125,7 @@ func (o *{{classname}}) Get{{name}}() {{vendorExtensions.x-go-base-type}} {
 // Deprecated
 {{/deprecated}}
 func (o *{{classname}}) Get{{name}}Ok() ({{^isArray}}{{^isFreeFormObject}}*{{/isFreeFormObject}}{{/isArray}}{{vendorExtensions.x-go-base-type}}, bool) {
-	if o == nil{{#isNullable}}{{#vendorExtensions.x-golang-is-container}} || isNil(o.{{name}}){{/vendorExtensions.x-golang-is-container}}{{/isNullable}} {
+	if o == nil{{#isNullable}}{{#vendorExtensions.x-golang-is-container}} || IsNil(o.{{name}}){{/vendorExtensions.x-golang-is-container}}{{/isNullable}} {
 {{^isFreeFormObject}}
 		return nil, false
 	{{/isFreeFormObject}}
@@ -171,7 +171,7 @@ func (o *{{classname}}) Set{{name}}(v {{vendorExtensions.x-go-base-type}}) {
 // Deprecated
 {{/deprecated}}
 func (o *{{classname}}) Get{{name}}() {{vendorExtensions.x-go-base-type}} {
-	if o == nil{{^isNullable}} || isNil(o.{{name}}){{/isNullable}}{{#isNullable}}{{^vendorExtensions.x-golang-is-container}} || isNil(o.{{name}}.Get()){{/vendorExtensions.x-golang-is-container}}{{/isNullable}} {
+	if o == nil{{^isNullable}} || IsNil(o.{{name}}){{/isNullable}}{{#isNullable}}{{^vendorExtensions.x-golang-is-container}} || IsNil(o.{{name}}.Get()){{/vendorExtensions.x-golang-is-container}}{{/isNullable}} {
 		var ret {{vendorExtensions.x-go-base-type}}
 		return ret
 	}
@@ -197,7 +197,7 @@ func (o *{{classname}}) Get{{name}}() {{vendorExtensions.x-go-base-type}} {
 // Deprecated
 {{/deprecated}}
 func (o *{{classname}}) Get{{name}}Ok() ({{^isArray}}{{^isFreeFormObject}}*{{/isFreeFormObject}}{{/isArray}}{{vendorExtensions.x-go-base-type}}, bool) {
-	if o == nil{{^isNullable}} || isNil(o.{{name}}){{/isNullable}}{{#isNullable}}{{#vendorExtensions.x-golang-is-container}} || isNil(o.{{name}}){{/vendorExtensions.x-golang-is-container}}{{/isNullable}} {
+	if o == nil{{^isNullable}} || IsNil(o.{{name}}){{/isNullable}}{{#isNullable}}{{#vendorExtensions.x-golang-is-container}} || IsNil(o.{{name}}){{/vendorExtensions.x-golang-is-container}}{{/isNullable}} {
 	{{^isFreeFormObject}}
 		return nil, false
 	{{/isFreeFormObject}}
@@ -220,7 +220,7 @@ func (o *{{classname}}) Get{{name}}Ok() ({{^isArray}}{{^isFreeFormObject}}*{{/is
 
 // Has{{name}} returns a boolean if a field has been set.
 func (o *{{classname}}) Has{{name}}() bool {
-	if o != nil && {{^isNullable}}!isNil(o.{{name}}){{/isNullable}}{{#isNullable}}{{#vendorExtensions.x-golang-is-container}}isNil(o.{{name}}){{/vendorExtensions.x-golang-is-container}}{{^vendorExtensions.x-golang-is-container}}o.{{name}}.IsSet(){{/vendorExtensions.x-golang-is-container}}{{/isNullable}} {
+	if o != nil && {{^isNullable}}!IsNil(o.{{name}}){{/isNullable}}{{#isNullable}}{{#vendorExtensions.x-golang-is-container}}IsNil(o.{{name}}){{/vendorExtensions.x-golang-is-container}}{{^vendorExtensions.x-golang-is-container}}o.{{name}}.IsSet(){{/vendorExtensions.x-golang-is-container}}{{/isNullable}} {
 		return true
 	}
 
@@ -316,7 +316,7 @@ func (o {{classname}}) ToMap() (map[string]interface{}, error) {
 	toSerialize["{{baseName}}"] = o.{{name}}
 	{{/required}}
 	{{^required}}
-	if !isNil(o.{{name}}) {
+	if !IsNil(o.{{name}}) {
 		toSerialize["{{baseName}}"] = o.{{name}}
 	}
 	{{/required}}
diff --git a/modules/openapi-generator/src/main/resources/go/utils.mustache b/modules/openapi-generator/src/main/resources/go/utils.mustache
index 5e97b9def76..8ba1109fc35 100644
--- a/modules/openapi-generator/src/main/resources/go/utils.mustache
+++ b/modules/openapi-generator/src/main/resources/go/utils.mustache
@@ -319,8 +319,8 @@ func (v *NullableTime) UnmarshalJSON(src []byte) error {
 	return json.Unmarshal(src, &v.value)
 }
 
-// isNil checks if an input is nil
-func isNil(i interface{}) bool {
+// IsNil checks if an input is nil
+func IsNil(i interface{}) bool {
 	if i == nil {
 		return true
 	}
diff --git a/samples/client/petstore/go/go-petstore/model_200_response.go b/samples/client/petstore/go/go-petstore/model_200_response.go
index 74749bc469a..f26632075bb 100644
--- a/samples/client/petstore/go/go-petstore/model_200_response.go
+++ b/samples/client/petstore/go/go-petstore/model_200_response.go
@@ -42,7 +42,7 @@ func NewModel200ResponseWithDefaults() *Model200Response {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *Model200Response) GetName() int32 {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret int32
 		return ret
 	}
@@ -52,7 +52,7 @@ func (o *Model200Response) GetName() int32 {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Model200Response) GetNameOk() (*int32, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -60,7 +60,7 @@ func (o *Model200Response) GetNameOk() (*int32, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *Model200Response) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -74,7 +74,7 @@ func (o *Model200Response) SetName(v int32) {
 
 // GetClass returns the Class field value if set, zero value otherwise.
 func (o *Model200Response) GetClass() string {
-	if o == nil || isNil(o.Class) {
+	if o == nil || IsNil(o.Class) {
 		var ret string
 		return ret
 	}
@@ -84,7 +84,7 @@ func (o *Model200Response) GetClass() string {
 // GetClassOk returns a tuple with the Class field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Model200Response) GetClassOk() (*string, bool) {
-	if o == nil || isNil(o.Class) {
+	if o == nil || IsNil(o.Class) {
 		return nil, false
 	}
 	return o.Class, true
@@ -92,7 +92,7 @@ func (o *Model200Response) GetClassOk() (*string, bool) {
 
 // HasClass returns a boolean if a field has been set.
 func (o *Model200Response) HasClass() bool {
-	if o != nil && !isNil(o.Class) {
+	if o != nil && !IsNil(o.Class) {
 		return true
 	}
 
@@ -114,10 +114,10 @@ func (o Model200Response) MarshalJSON() ([]byte, error) {
 
 func (o Model200Response) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
-	if !isNil(o.Class) {
+	if !IsNil(o.Class) {
 		toSerialize["class"] = o.Class
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_additional_properties_any_type.go b/samples/client/petstore/go/go-petstore/model_additional_properties_any_type.go
index bce81de1548..9fd12d021ba 100644
--- a/samples/client/petstore/go/go-petstore/model_additional_properties_any_type.go
+++ b/samples/client/petstore/go/go-petstore/model_additional_properties_any_type.go
@@ -41,7 +41,7 @@ func NewAdditionalPropertiesAnyTypeWithDefaults() *AdditionalPropertiesAnyType {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *AdditionalPropertiesAnyType) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *AdditionalPropertiesAnyType) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesAnyType) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -59,7 +59,7 @@ func (o *AdditionalPropertiesAnyType) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *AdditionalPropertiesAnyType) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o AdditionalPropertiesAnyType) MarshalJSON() ([]byte, error) {
 
 func (o AdditionalPropertiesAnyType) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_additional_properties_array.go b/samples/client/petstore/go/go-petstore/model_additional_properties_array.go
index 824daac9580..9cbb26fec0d 100644
--- a/samples/client/petstore/go/go-petstore/model_additional_properties_array.go
+++ b/samples/client/petstore/go/go-petstore/model_additional_properties_array.go
@@ -41,7 +41,7 @@ func NewAdditionalPropertiesArrayWithDefaults() *AdditionalPropertiesArray {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *AdditionalPropertiesArray) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *AdditionalPropertiesArray) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesArray) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -59,7 +59,7 @@ func (o *AdditionalPropertiesArray) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *AdditionalPropertiesArray) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o AdditionalPropertiesArray) MarshalJSON() ([]byte, error) {
 
 func (o AdditionalPropertiesArray) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_additional_properties_boolean.go b/samples/client/petstore/go/go-petstore/model_additional_properties_boolean.go
index e7238d39185..5659b277e6d 100644
--- a/samples/client/petstore/go/go-petstore/model_additional_properties_boolean.go
+++ b/samples/client/petstore/go/go-petstore/model_additional_properties_boolean.go
@@ -41,7 +41,7 @@ func NewAdditionalPropertiesBooleanWithDefaults() *AdditionalPropertiesBoolean {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *AdditionalPropertiesBoolean) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *AdditionalPropertiesBoolean) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesBoolean) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -59,7 +59,7 @@ func (o *AdditionalPropertiesBoolean) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *AdditionalPropertiesBoolean) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o AdditionalPropertiesBoolean) MarshalJSON() ([]byte, error) {
 
 func (o AdditionalPropertiesBoolean) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_additional_properties_class.go b/samples/client/petstore/go/go-petstore/model_additional_properties_class.go
index 3b724096df4..5abc8a844b1 100644
--- a/samples/client/petstore/go/go-petstore/model_additional_properties_class.go
+++ b/samples/client/petstore/go/go-petstore/model_additional_properties_class.go
@@ -51,7 +51,7 @@ func NewAdditionalPropertiesClassWithDefaults() *AdditionalPropertiesClass {
 
 // GetMapString returns the MapString field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetMapString() map[string]string {
-	if o == nil || isNil(o.MapString) {
+	if o == nil || IsNil(o.MapString) {
 		var ret map[string]string
 		return ret
 	}
@@ -61,7 +61,7 @@ func (o *AdditionalPropertiesClass) GetMapString() map[string]string {
 // GetMapStringOk returns a tuple with the MapString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetMapStringOk() (*map[string]string, bool) {
-	if o == nil || isNil(o.MapString) {
+	if o == nil || IsNil(o.MapString) {
 		return nil, false
 	}
 	return o.MapString, true
@@ -69,7 +69,7 @@ func (o *AdditionalPropertiesClass) GetMapStringOk() (*map[string]string, bool)
 
 // HasMapString returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasMapString() bool {
-	if o != nil && !isNil(o.MapString) {
+	if o != nil && !IsNil(o.MapString) {
 		return true
 	}
 
@@ -83,7 +83,7 @@ func (o *AdditionalPropertiesClass) SetMapString(v map[string]string) {
 
 // GetMapNumber returns the MapNumber field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetMapNumber() map[string]float32 {
-	if o == nil || isNil(o.MapNumber) {
+	if o == nil || IsNil(o.MapNumber) {
 		var ret map[string]float32
 		return ret
 	}
@@ -93,7 +93,7 @@ func (o *AdditionalPropertiesClass) GetMapNumber() map[string]float32 {
 // GetMapNumberOk returns a tuple with the MapNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetMapNumberOk() (*map[string]float32, bool) {
-	if o == nil || isNil(o.MapNumber) {
+	if o == nil || IsNil(o.MapNumber) {
 		return nil, false
 	}
 	return o.MapNumber, true
@@ -101,7 +101,7 @@ func (o *AdditionalPropertiesClass) GetMapNumberOk() (*map[string]float32, bool)
 
 // HasMapNumber returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasMapNumber() bool {
-	if o != nil && !isNil(o.MapNumber) {
+	if o != nil && !IsNil(o.MapNumber) {
 		return true
 	}
 
@@ -115,7 +115,7 @@ func (o *AdditionalPropertiesClass) SetMapNumber(v map[string]float32) {
 
 // GetMapInteger returns the MapInteger field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetMapInteger() map[string]int32 {
-	if o == nil || isNil(o.MapInteger) {
+	if o == nil || IsNil(o.MapInteger) {
 		var ret map[string]int32
 		return ret
 	}
@@ -125,7 +125,7 @@ func (o *AdditionalPropertiesClass) GetMapInteger() map[string]int32 {
 // GetMapIntegerOk returns a tuple with the MapInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetMapIntegerOk() (*map[string]int32, bool) {
-	if o == nil || isNil(o.MapInteger) {
+	if o == nil || IsNil(o.MapInteger) {
 		return nil, false
 	}
 	return o.MapInteger, true
@@ -133,7 +133,7 @@ func (o *AdditionalPropertiesClass) GetMapIntegerOk() (*map[string]int32, bool)
 
 // HasMapInteger returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasMapInteger() bool {
-	if o != nil && !isNil(o.MapInteger) {
+	if o != nil && !IsNil(o.MapInteger) {
 		return true
 	}
 
@@ -147,7 +147,7 @@ func (o *AdditionalPropertiesClass) SetMapInteger(v map[string]int32) {
 
 // GetMapBoolean returns the MapBoolean field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetMapBoolean() map[string]bool {
-	if o == nil || isNil(o.MapBoolean) {
+	if o == nil || IsNil(o.MapBoolean) {
 		var ret map[string]bool
 		return ret
 	}
@@ -157,7 +157,7 @@ func (o *AdditionalPropertiesClass) GetMapBoolean() map[string]bool {
 // GetMapBooleanOk returns a tuple with the MapBoolean field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetMapBooleanOk() (*map[string]bool, bool) {
-	if o == nil || isNil(o.MapBoolean) {
+	if o == nil || IsNil(o.MapBoolean) {
 		return nil, false
 	}
 	return o.MapBoolean, true
@@ -165,7 +165,7 @@ func (o *AdditionalPropertiesClass) GetMapBooleanOk() (*map[string]bool, bool) {
 
 // HasMapBoolean returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasMapBoolean() bool {
-	if o != nil && !isNil(o.MapBoolean) {
+	if o != nil && !IsNil(o.MapBoolean) {
 		return true
 	}
 
@@ -179,7 +179,7 @@ func (o *AdditionalPropertiesClass) SetMapBoolean(v map[string]bool) {
 
 // GetMapArrayInteger returns the MapArrayInteger field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetMapArrayInteger() map[string][]int32 {
-	if o == nil || isNil(o.MapArrayInteger) {
+	if o == nil || IsNil(o.MapArrayInteger) {
 		var ret map[string][]int32
 		return ret
 	}
@@ -189,7 +189,7 @@ func (o *AdditionalPropertiesClass) GetMapArrayInteger() map[string][]int32 {
 // GetMapArrayIntegerOk returns a tuple with the MapArrayInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetMapArrayIntegerOk() (*map[string][]int32, bool) {
-	if o == nil || isNil(o.MapArrayInteger) {
+	if o == nil || IsNil(o.MapArrayInteger) {
 		return nil, false
 	}
 	return o.MapArrayInteger, true
@@ -197,7 +197,7 @@ func (o *AdditionalPropertiesClass) GetMapArrayIntegerOk() (*map[string][]int32,
 
 // HasMapArrayInteger returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasMapArrayInteger() bool {
-	if o != nil && !isNil(o.MapArrayInteger) {
+	if o != nil && !IsNil(o.MapArrayInteger) {
 		return true
 	}
 
@@ -211,7 +211,7 @@ func (o *AdditionalPropertiesClass) SetMapArrayInteger(v map[string][]int32) {
 
 // GetMapArrayAnytype returns the MapArrayAnytype field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetMapArrayAnytype() map[string][]map[string]interface{} {
-	if o == nil || isNil(o.MapArrayAnytype) {
+	if o == nil || IsNil(o.MapArrayAnytype) {
 		var ret map[string][]map[string]interface{}
 		return ret
 	}
@@ -221,7 +221,7 @@ func (o *AdditionalPropertiesClass) GetMapArrayAnytype() map[string][]map[string
 // GetMapArrayAnytypeOk returns a tuple with the MapArrayAnytype field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetMapArrayAnytypeOk() (*map[string][]map[string]interface{}, bool) {
-	if o == nil || isNil(o.MapArrayAnytype) {
+	if o == nil || IsNil(o.MapArrayAnytype) {
 		return nil, false
 	}
 	return o.MapArrayAnytype, true
@@ -229,7 +229,7 @@ func (o *AdditionalPropertiesClass) GetMapArrayAnytypeOk() (*map[string][]map[st
 
 // HasMapArrayAnytype returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasMapArrayAnytype() bool {
-	if o != nil && !isNil(o.MapArrayAnytype) {
+	if o != nil && !IsNil(o.MapArrayAnytype) {
 		return true
 	}
 
@@ -243,7 +243,7 @@ func (o *AdditionalPropertiesClass) SetMapArrayAnytype(v map[string][]map[string
 
 // GetMapMapString returns the MapMapString field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetMapMapString() map[string]map[string]string {
-	if o == nil || isNil(o.MapMapString) {
+	if o == nil || IsNil(o.MapMapString) {
 		var ret map[string]map[string]string
 		return ret
 	}
@@ -253,7 +253,7 @@ func (o *AdditionalPropertiesClass) GetMapMapString() map[string]map[string]stri
 // GetMapMapStringOk returns a tuple with the MapMapString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetMapMapStringOk() (*map[string]map[string]string, bool) {
-	if o == nil || isNil(o.MapMapString) {
+	if o == nil || IsNil(o.MapMapString) {
 		return nil, false
 	}
 	return o.MapMapString, true
@@ -261,7 +261,7 @@ func (o *AdditionalPropertiesClass) GetMapMapStringOk() (*map[string]map[string]
 
 // HasMapMapString returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasMapMapString() bool {
-	if o != nil && !isNil(o.MapMapString) {
+	if o != nil && !IsNil(o.MapMapString) {
 		return true
 	}
 
@@ -275,7 +275,7 @@ func (o *AdditionalPropertiesClass) SetMapMapString(v map[string]map[string]stri
 
 // GetMapMapAnytype returns the MapMapAnytype field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetMapMapAnytype() map[string]map[string]map[string]interface{} {
-	if o == nil || isNil(o.MapMapAnytype) {
+	if o == nil || IsNil(o.MapMapAnytype) {
 		var ret map[string]map[string]map[string]interface{}
 		return ret
 	}
@@ -285,7 +285,7 @@ func (o *AdditionalPropertiesClass) GetMapMapAnytype() map[string]map[string]map
 // GetMapMapAnytypeOk returns a tuple with the MapMapAnytype field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetMapMapAnytypeOk() (*map[string]map[string]map[string]interface{}, bool) {
-	if o == nil || isNil(o.MapMapAnytype) {
+	if o == nil || IsNil(o.MapMapAnytype) {
 		return nil, false
 	}
 	return o.MapMapAnytype, true
@@ -293,7 +293,7 @@ func (o *AdditionalPropertiesClass) GetMapMapAnytypeOk() (*map[string]map[string
 
 // HasMapMapAnytype returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasMapMapAnytype() bool {
-	if o != nil && !isNil(o.MapMapAnytype) {
+	if o != nil && !IsNil(o.MapMapAnytype) {
 		return true
 	}
 
@@ -307,7 +307,7 @@ func (o *AdditionalPropertiesClass) SetMapMapAnytype(v map[string]map[string]map
 
 // GetAnytype1 returns the Anytype1 field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetAnytype1() map[string]interface{} {
-	if o == nil || isNil(o.Anytype1) {
+	if o == nil || IsNil(o.Anytype1) {
 		var ret map[string]interface{}
 		return ret
 	}
@@ -317,7 +317,7 @@ func (o *AdditionalPropertiesClass) GetAnytype1() map[string]interface{} {
 // GetAnytype1Ok returns a tuple with the Anytype1 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetAnytype1Ok() (map[string]interface{}, bool) {
-	if o == nil || isNil(o.Anytype1) {
+	if o == nil || IsNil(o.Anytype1) {
 		return map[string]interface{}{}, false
 	}
 	return o.Anytype1, true
@@ -325,7 +325,7 @@ func (o *AdditionalPropertiesClass) GetAnytype1Ok() (map[string]interface{}, boo
 
 // HasAnytype1 returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasAnytype1() bool {
-	if o != nil && !isNil(o.Anytype1) {
+	if o != nil && !IsNil(o.Anytype1) {
 		return true
 	}
 
@@ -339,7 +339,7 @@ func (o *AdditionalPropertiesClass) SetAnytype1(v map[string]interface{}) {
 
 // GetAnytype2 returns the Anytype2 field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetAnytype2() map[string]interface{} {
-	if o == nil || isNil(o.Anytype2) {
+	if o == nil || IsNil(o.Anytype2) {
 		var ret map[string]interface{}
 		return ret
 	}
@@ -349,7 +349,7 @@ func (o *AdditionalPropertiesClass) GetAnytype2() map[string]interface{} {
 // GetAnytype2Ok returns a tuple with the Anytype2 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetAnytype2Ok() (map[string]interface{}, bool) {
-	if o == nil || isNil(o.Anytype2) {
+	if o == nil || IsNil(o.Anytype2) {
 		return map[string]interface{}{}, false
 	}
 	return o.Anytype2, true
@@ -357,7 +357,7 @@ func (o *AdditionalPropertiesClass) GetAnytype2Ok() (map[string]interface{}, boo
 
 // HasAnytype2 returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasAnytype2() bool {
-	if o != nil && !isNil(o.Anytype2) {
+	if o != nil && !IsNil(o.Anytype2) {
 		return true
 	}
 
@@ -371,7 +371,7 @@ func (o *AdditionalPropertiesClass) SetAnytype2(v map[string]interface{}) {
 
 // GetAnytype3 returns the Anytype3 field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetAnytype3() map[string]interface{} {
-	if o == nil || isNil(o.Anytype3) {
+	if o == nil || IsNil(o.Anytype3) {
 		var ret map[string]interface{}
 		return ret
 	}
@@ -381,7 +381,7 @@ func (o *AdditionalPropertiesClass) GetAnytype3() map[string]interface{} {
 // GetAnytype3Ok returns a tuple with the Anytype3 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetAnytype3Ok() (map[string]interface{}, bool) {
-	if o == nil || isNil(o.Anytype3) {
+	if o == nil || IsNil(o.Anytype3) {
 		return map[string]interface{}{}, false
 	}
 	return o.Anytype3, true
@@ -389,7 +389,7 @@ func (o *AdditionalPropertiesClass) GetAnytype3Ok() (map[string]interface{}, boo
 
 // HasAnytype3 returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasAnytype3() bool {
-	if o != nil && !isNil(o.Anytype3) {
+	if o != nil && !IsNil(o.Anytype3) {
 		return true
 	}
 
@@ -411,37 +411,37 @@ func (o AdditionalPropertiesClass) MarshalJSON() ([]byte, error) {
 
 func (o AdditionalPropertiesClass) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.MapString) {
+	if !IsNil(o.MapString) {
 		toSerialize["map_string"] = o.MapString
 	}
-	if !isNil(o.MapNumber) {
+	if !IsNil(o.MapNumber) {
 		toSerialize["map_number"] = o.MapNumber
 	}
-	if !isNil(o.MapInteger) {
+	if !IsNil(o.MapInteger) {
 		toSerialize["map_integer"] = o.MapInteger
 	}
-	if !isNil(o.MapBoolean) {
+	if !IsNil(o.MapBoolean) {
 		toSerialize["map_boolean"] = o.MapBoolean
 	}
-	if !isNil(o.MapArrayInteger) {
+	if !IsNil(o.MapArrayInteger) {
 		toSerialize["map_array_integer"] = o.MapArrayInteger
 	}
-	if !isNil(o.MapArrayAnytype) {
+	if !IsNil(o.MapArrayAnytype) {
 		toSerialize["map_array_anytype"] = o.MapArrayAnytype
 	}
-	if !isNil(o.MapMapString) {
+	if !IsNil(o.MapMapString) {
 		toSerialize["map_map_string"] = o.MapMapString
 	}
-	if !isNil(o.MapMapAnytype) {
+	if !IsNil(o.MapMapAnytype) {
 		toSerialize["map_map_anytype"] = o.MapMapAnytype
 	}
-	if !isNil(o.Anytype1) {
+	if !IsNil(o.Anytype1) {
 		toSerialize["anytype_1"] = o.Anytype1
 	}
-	if !isNil(o.Anytype2) {
+	if !IsNil(o.Anytype2) {
 		toSerialize["anytype_2"] = o.Anytype2
 	}
-	if !isNil(o.Anytype3) {
+	if !IsNil(o.Anytype3) {
 		toSerialize["anytype_3"] = o.Anytype3
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_additional_properties_integer.go b/samples/client/petstore/go/go-petstore/model_additional_properties_integer.go
index a2daa0c699c..9873644fe54 100644
--- a/samples/client/petstore/go/go-petstore/model_additional_properties_integer.go
+++ b/samples/client/petstore/go/go-petstore/model_additional_properties_integer.go
@@ -41,7 +41,7 @@ func NewAdditionalPropertiesIntegerWithDefaults() *AdditionalPropertiesInteger {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *AdditionalPropertiesInteger) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *AdditionalPropertiesInteger) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesInteger) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -59,7 +59,7 @@ func (o *AdditionalPropertiesInteger) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *AdditionalPropertiesInteger) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o AdditionalPropertiesInteger) MarshalJSON() ([]byte, error) {
 
 func (o AdditionalPropertiesInteger) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_additional_properties_number.go b/samples/client/petstore/go/go-petstore/model_additional_properties_number.go
index 1334301945c..a1cb5187a5b 100644
--- a/samples/client/petstore/go/go-petstore/model_additional_properties_number.go
+++ b/samples/client/petstore/go/go-petstore/model_additional_properties_number.go
@@ -41,7 +41,7 @@ func NewAdditionalPropertiesNumberWithDefaults() *AdditionalPropertiesNumber {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *AdditionalPropertiesNumber) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *AdditionalPropertiesNumber) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesNumber) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -59,7 +59,7 @@ func (o *AdditionalPropertiesNumber) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *AdditionalPropertiesNumber) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o AdditionalPropertiesNumber) MarshalJSON() ([]byte, error) {
 
 func (o AdditionalPropertiesNumber) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_additional_properties_object.go b/samples/client/petstore/go/go-petstore/model_additional_properties_object.go
index 8e05068b039..201a624e05d 100644
--- a/samples/client/petstore/go/go-petstore/model_additional_properties_object.go
+++ b/samples/client/petstore/go/go-petstore/model_additional_properties_object.go
@@ -41,7 +41,7 @@ func NewAdditionalPropertiesObjectWithDefaults() *AdditionalPropertiesObject {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *AdditionalPropertiesObject) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *AdditionalPropertiesObject) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesObject) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -59,7 +59,7 @@ func (o *AdditionalPropertiesObject) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *AdditionalPropertiesObject) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o AdditionalPropertiesObject) MarshalJSON() ([]byte, error) {
 
 func (o AdditionalPropertiesObject) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_additional_properties_string.go b/samples/client/petstore/go/go-petstore/model_additional_properties_string.go
index 88f98c982a9..df649a265a1 100644
--- a/samples/client/petstore/go/go-petstore/model_additional_properties_string.go
+++ b/samples/client/petstore/go/go-petstore/model_additional_properties_string.go
@@ -41,7 +41,7 @@ func NewAdditionalPropertiesStringWithDefaults() *AdditionalPropertiesString {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *AdditionalPropertiesString) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *AdditionalPropertiesString) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesString) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -59,7 +59,7 @@ func (o *AdditionalPropertiesString) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *AdditionalPropertiesString) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o AdditionalPropertiesString) MarshalJSON() ([]byte, error) {
 
 func (o AdditionalPropertiesString) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_animal.go b/samples/client/petstore/go/go-petstore/model_animal.go
index 58a0f7afe31..a884b8473f6 100644
--- a/samples/client/petstore/go/go-petstore/model_animal.go
+++ b/samples/client/petstore/go/go-petstore/model_animal.go
@@ -71,7 +71,7 @@ func (o *Animal) SetClassName(v string) {
 
 // GetColor returns the Color field value if set, zero value otherwise.
 func (o *Animal) GetColor() string {
-	if o == nil || isNil(o.Color) {
+	if o == nil || IsNil(o.Color) {
 		var ret string
 		return ret
 	}
@@ -81,7 +81,7 @@ func (o *Animal) GetColor() string {
 // GetColorOk returns a tuple with the Color field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Animal) GetColorOk() (*string, bool) {
-	if o == nil || isNil(o.Color) {
+	if o == nil || IsNil(o.Color) {
 		return nil, false
 	}
 	return o.Color, true
@@ -89,7 +89,7 @@ func (o *Animal) GetColorOk() (*string, bool) {
 
 // HasColor returns a boolean if a field has been set.
 func (o *Animal) HasColor() bool {
-	if o != nil && !isNil(o.Color) {
+	if o != nil && !IsNil(o.Color) {
 		return true
 	}
 
@@ -112,7 +112,7 @@ func (o Animal) MarshalJSON() ([]byte, error) {
 func (o Animal) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
 	toSerialize["className"] = o.ClassName
-	if !isNil(o.Color) {
+	if !IsNil(o.Color) {
 		toSerialize["color"] = o.Color
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_api_response.go b/samples/client/petstore/go/go-petstore/model_api_response.go
index 6e05e5fa516..60ed1b2100b 100644
--- a/samples/client/petstore/go/go-petstore/model_api_response.go
+++ b/samples/client/petstore/go/go-petstore/model_api_response.go
@@ -43,7 +43,7 @@ func NewApiResponseWithDefaults() *ApiResponse {
 
 // GetCode returns the Code field value if set, zero value otherwise.
 func (o *ApiResponse) GetCode() int32 {
-	if o == nil || isNil(o.Code) {
+	if o == nil || IsNil(o.Code) {
 		var ret int32
 		return ret
 	}
@@ -53,7 +53,7 @@ func (o *ApiResponse) GetCode() int32 {
 // GetCodeOk returns a tuple with the Code field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ApiResponse) GetCodeOk() (*int32, bool) {
-	if o == nil || isNil(o.Code) {
+	if o == nil || IsNil(o.Code) {
 		return nil, false
 	}
 	return o.Code, true
@@ -61,7 +61,7 @@ func (o *ApiResponse) GetCodeOk() (*int32, bool) {
 
 // HasCode returns a boolean if a field has been set.
 func (o *ApiResponse) HasCode() bool {
-	if o != nil && !isNil(o.Code) {
+	if o != nil && !IsNil(o.Code) {
 		return true
 	}
 
@@ -75,7 +75,7 @@ func (o *ApiResponse) SetCode(v int32) {
 
 // GetType returns the Type field value if set, zero value otherwise.
 func (o *ApiResponse) GetType() string {
-	if o == nil || isNil(o.Type) {
+	if o == nil || IsNil(o.Type) {
 		var ret string
 		return ret
 	}
@@ -85,7 +85,7 @@ func (o *ApiResponse) GetType() string {
 // GetTypeOk returns a tuple with the Type field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ApiResponse) GetTypeOk() (*string, bool) {
-	if o == nil || isNil(o.Type) {
+	if o == nil || IsNil(o.Type) {
 		return nil, false
 	}
 	return o.Type, true
@@ -93,7 +93,7 @@ func (o *ApiResponse) GetTypeOk() (*string, bool) {
 
 // HasType returns a boolean if a field has been set.
 func (o *ApiResponse) HasType() bool {
-	if o != nil && !isNil(o.Type) {
+	if o != nil && !IsNil(o.Type) {
 		return true
 	}
 
@@ -107,7 +107,7 @@ func (o *ApiResponse) SetType(v string) {
 
 // GetMessage returns the Message field value if set, zero value otherwise.
 func (o *ApiResponse) GetMessage() string {
-	if o == nil || isNil(o.Message) {
+	if o == nil || IsNil(o.Message) {
 		var ret string
 		return ret
 	}
@@ -117,7 +117,7 @@ func (o *ApiResponse) GetMessage() string {
 // GetMessageOk returns a tuple with the Message field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ApiResponse) GetMessageOk() (*string, bool) {
-	if o == nil || isNil(o.Message) {
+	if o == nil || IsNil(o.Message) {
 		return nil, false
 	}
 	return o.Message, true
@@ -125,7 +125,7 @@ func (o *ApiResponse) GetMessageOk() (*string, bool) {
 
 // HasMessage returns a boolean if a field has been set.
 func (o *ApiResponse) HasMessage() bool {
-	if o != nil && !isNil(o.Message) {
+	if o != nil && !IsNil(o.Message) {
 		return true
 	}
 
@@ -147,13 +147,13 @@ func (o ApiResponse) MarshalJSON() ([]byte, error) {
 
 func (o ApiResponse) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Code) {
+	if !IsNil(o.Code) {
 		toSerialize["code"] = o.Code
 	}
-	if !isNil(o.Type) {
+	if !IsNil(o.Type) {
 		toSerialize["type"] = o.Type
 	}
-	if !isNil(o.Message) {
+	if !IsNil(o.Message) {
 		toSerialize["message"] = o.Message
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_array_of_array_of_number_only.go b/samples/client/petstore/go/go-petstore/model_array_of_array_of_number_only.go
index f088603caaf..db9c18aa620 100644
--- a/samples/client/petstore/go/go-petstore/model_array_of_array_of_number_only.go
+++ b/samples/client/petstore/go/go-petstore/model_array_of_array_of_number_only.go
@@ -41,7 +41,7 @@ func NewArrayOfArrayOfNumberOnlyWithDefaults() *ArrayOfArrayOfNumberOnly {
 
 // GetArrayArrayNumber returns the ArrayArrayNumber field value if set, zero value otherwise.
 func (o *ArrayOfArrayOfNumberOnly) GetArrayArrayNumber() [][]float32 {
-	if o == nil || isNil(o.ArrayArrayNumber) {
+	if o == nil || IsNil(o.ArrayArrayNumber) {
 		var ret [][]float32
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *ArrayOfArrayOfNumberOnly) GetArrayArrayNumber() [][]float32 {
 // GetArrayArrayNumberOk returns a tuple with the ArrayArrayNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ArrayOfArrayOfNumberOnly) GetArrayArrayNumberOk() ([][]float32, bool) {
-	if o == nil || isNil(o.ArrayArrayNumber) {
+	if o == nil || IsNil(o.ArrayArrayNumber) {
 		return nil, false
 	}
 	return o.ArrayArrayNumber, true
@@ -59,7 +59,7 @@ func (o *ArrayOfArrayOfNumberOnly) GetArrayArrayNumberOk() ([][]float32, bool) {
 
 // HasArrayArrayNumber returns a boolean if a field has been set.
 func (o *ArrayOfArrayOfNumberOnly) HasArrayArrayNumber() bool {
-	if o != nil && !isNil(o.ArrayArrayNumber) {
+	if o != nil && !IsNil(o.ArrayArrayNumber) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o ArrayOfArrayOfNumberOnly) MarshalJSON() ([]byte, error) {
 
 func (o ArrayOfArrayOfNumberOnly) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.ArrayArrayNumber) {
+	if !IsNil(o.ArrayArrayNumber) {
 		toSerialize["ArrayArrayNumber"] = o.ArrayArrayNumber
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_array_of_number_only.go b/samples/client/petstore/go/go-petstore/model_array_of_number_only.go
index 9a53a85344b..636ec8e1294 100644
--- a/samples/client/petstore/go/go-petstore/model_array_of_number_only.go
+++ b/samples/client/petstore/go/go-petstore/model_array_of_number_only.go
@@ -41,7 +41,7 @@ func NewArrayOfNumberOnlyWithDefaults() *ArrayOfNumberOnly {
 
 // GetArrayNumber returns the ArrayNumber field value if set, zero value otherwise.
 func (o *ArrayOfNumberOnly) GetArrayNumber() []float32 {
-	if o == nil || isNil(o.ArrayNumber) {
+	if o == nil || IsNil(o.ArrayNumber) {
 		var ret []float32
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *ArrayOfNumberOnly) GetArrayNumber() []float32 {
 // GetArrayNumberOk returns a tuple with the ArrayNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ArrayOfNumberOnly) GetArrayNumberOk() ([]float32, bool) {
-	if o == nil || isNil(o.ArrayNumber) {
+	if o == nil || IsNil(o.ArrayNumber) {
 		return nil, false
 	}
 	return o.ArrayNumber, true
@@ -59,7 +59,7 @@ func (o *ArrayOfNumberOnly) GetArrayNumberOk() ([]float32, bool) {
 
 // HasArrayNumber returns a boolean if a field has been set.
 func (o *ArrayOfNumberOnly) HasArrayNumber() bool {
-	if o != nil && !isNil(o.ArrayNumber) {
+	if o != nil && !IsNil(o.ArrayNumber) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o ArrayOfNumberOnly) MarshalJSON() ([]byte, error) {
 
 func (o ArrayOfNumberOnly) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.ArrayNumber) {
+	if !IsNil(o.ArrayNumber) {
 		toSerialize["ArrayNumber"] = o.ArrayNumber
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_array_test_.go b/samples/client/petstore/go/go-petstore/model_array_test_.go
index 963dd19344b..2b95a674682 100644
--- a/samples/client/petstore/go/go-petstore/model_array_test_.go
+++ b/samples/client/petstore/go/go-petstore/model_array_test_.go
@@ -43,7 +43,7 @@ func NewArrayTestWithDefaults() *ArrayTest {
 
 // GetArrayOfString returns the ArrayOfString field value if set, zero value otherwise.
 func (o *ArrayTest) GetArrayOfString() []string {
-	if o == nil || isNil(o.ArrayOfString) {
+	if o == nil || IsNil(o.ArrayOfString) {
 		var ret []string
 		return ret
 	}
@@ -53,7 +53,7 @@ func (o *ArrayTest) GetArrayOfString() []string {
 // GetArrayOfStringOk returns a tuple with the ArrayOfString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ArrayTest) GetArrayOfStringOk() ([]string, bool) {
-	if o == nil || isNil(o.ArrayOfString) {
+	if o == nil || IsNil(o.ArrayOfString) {
 		return nil, false
 	}
 	return o.ArrayOfString, true
@@ -61,7 +61,7 @@ func (o *ArrayTest) GetArrayOfStringOk() ([]string, bool) {
 
 // HasArrayOfString returns a boolean if a field has been set.
 func (o *ArrayTest) HasArrayOfString() bool {
-	if o != nil && !isNil(o.ArrayOfString) {
+	if o != nil && !IsNil(o.ArrayOfString) {
 		return true
 	}
 
@@ -75,7 +75,7 @@ func (o *ArrayTest) SetArrayOfString(v []string) {
 
 // GetArrayArrayOfInteger returns the ArrayArrayOfInteger field value if set, zero value otherwise.
 func (o *ArrayTest) GetArrayArrayOfInteger() [][]int64 {
-	if o == nil || isNil(o.ArrayArrayOfInteger) {
+	if o == nil || IsNil(o.ArrayArrayOfInteger) {
 		var ret [][]int64
 		return ret
 	}
@@ -85,7 +85,7 @@ func (o *ArrayTest) GetArrayArrayOfInteger() [][]int64 {
 // GetArrayArrayOfIntegerOk returns a tuple with the ArrayArrayOfInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ArrayTest) GetArrayArrayOfIntegerOk() ([][]int64, bool) {
-	if o == nil || isNil(o.ArrayArrayOfInteger) {
+	if o == nil || IsNil(o.ArrayArrayOfInteger) {
 		return nil, false
 	}
 	return o.ArrayArrayOfInteger, true
@@ -93,7 +93,7 @@ func (o *ArrayTest) GetArrayArrayOfIntegerOk() ([][]int64, bool) {
 
 // HasArrayArrayOfInteger returns a boolean if a field has been set.
 func (o *ArrayTest) HasArrayArrayOfInteger() bool {
-	if o != nil && !isNil(o.ArrayArrayOfInteger) {
+	if o != nil && !IsNil(o.ArrayArrayOfInteger) {
 		return true
 	}
 
@@ -107,7 +107,7 @@ func (o *ArrayTest) SetArrayArrayOfInteger(v [][]int64) {
 
 // GetArrayArrayOfModel returns the ArrayArrayOfModel field value if set, zero value otherwise.
 func (o *ArrayTest) GetArrayArrayOfModel() [][]ReadOnlyFirst {
-	if o == nil || isNil(o.ArrayArrayOfModel) {
+	if o == nil || IsNil(o.ArrayArrayOfModel) {
 		var ret [][]ReadOnlyFirst
 		return ret
 	}
@@ -117,7 +117,7 @@ func (o *ArrayTest) GetArrayArrayOfModel() [][]ReadOnlyFirst {
 // GetArrayArrayOfModelOk returns a tuple with the ArrayArrayOfModel field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ArrayTest) GetArrayArrayOfModelOk() ([][]ReadOnlyFirst, bool) {
-	if o == nil || isNil(o.ArrayArrayOfModel) {
+	if o == nil || IsNil(o.ArrayArrayOfModel) {
 		return nil, false
 	}
 	return o.ArrayArrayOfModel, true
@@ -125,7 +125,7 @@ func (o *ArrayTest) GetArrayArrayOfModelOk() ([][]ReadOnlyFirst, bool) {
 
 // HasArrayArrayOfModel returns a boolean if a field has been set.
 func (o *ArrayTest) HasArrayArrayOfModel() bool {
-	if o != nil && !isNil(o.ArrayArrayOfModel) {
+	if o != nil && !IsNil(o.ArrayArrayOfModel) {
 		return true
 	}
 
@@ -147,13 +147,13 @@ func (o ArrayTest) MarshalJSON() ([]byte, error) {
 
 func (o ArrayTest) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.ArrayOfString) {
+	if !IsNil(o.ArrayOfString) {
 		toSerialize["array_of_string"] = o.ArrayOfString
 	}
-	if !isNil(o.ArrayArrayOfInteger) {
+	if !IsNil(o.ArrayArrayOfInteger) {
 		toSerialize["array_array_of_integer"] = o.ArrayArrayOfInteger
 	}
-	if !isNil(o.ArrayArrayOfModel) {
+	if !IsNil(o.ArrayArrayOfModel) {
 		toSerialize["array_array_of_model"] = o.ArrayArrayOfModel
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_big_cat.go b/samples/client/petstore/go/go-petstore/model_big_cat.go
index f624b3db92b..503a742ab8f 100644
--- a/samples/client/petstore/go/go-petstore/model_big_cat.go
+++ b/samples/client/petstore/go/go-petstore/model_big_cat.go
@@ -45,7 +45,7 @@ func NewBigCatWithDefaults() *BigCat {
 
 // GetKind returns the Kind field value if set, zero value otherwise.
 func (o *BigCat) GetKind() string {
-	if o == nil || isNil(o.Kind) {
+	if o == nil || IsNil(o.Kind) {
 		var ret string
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *BigCat) GetKind() string {
 // GetKindOk returns a tuple with the Kind field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *BigCat) GetKindOk() (*string, bool) {
-	if o == nil || isNil(o.Kind) {
+	if o == nil || IsNil(o.Kind) {
 		return nil, false
 	}
 	return o.Kind, true
@@ -63,7 +63,7 @@ func (o *BigCat) GetKindOk() (*string, bool) {
 
 // HasKind returns a boolean if a field has been set.
 func (o *BigCat) HasKind() bool {
-	if o != nil && !isNil(o.Kind) {
+	if o != nil && !IsNil(o.Kind) {
 		return true
 	}
 
@@ -93,7 +93,7 @@ func (o BigCat) ToMap() (map[string]interface{}, error) {
 	if errCat != nil {
 		return map[string]interface{}{}, errCat
 	}
-	if !isNil(o.Kind) {
+	if !IsNil(o.Kind) {
 		toSerialize["kind"] = o.Kind
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_big_cat_all_of.go b/samples/client/petstore/go/go-petstore/model_big_cat_all_of.go
index 74cc3c64f81..bd0486c3825 100644
--- a/samples/client/petstore/go/go-petstore/model_big_cat_all_of.go
+++ b/samples/client/petstore/go/go-petstore/model_big_cat_all_of.go
@@ -41,7 +41,7 @@ func NewBigCatAllOfWithDefaults() *BigCatAllOf {
 
 // GetKind returns the Kind field value if set, zero value otherwise.
 func (o *BigCatAllOf) GetKind() string {
-	if o == nil || isNil(o.Kind) {
+	if o == nil || IsNil(o.Kind) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *BigCatAllOf) GetKind() string {
 // GetKindOk returns a tuple with the Kind field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *BigCatAllOf) GetKindOk() (*string, bool) {
-	if o == nil || isNil(o.Kind) {
+	if o == nil || IsNil(o.Kind) {
 		return nil, false
 	}
 	return o.Kind, true
@@ -59,7 +59,7 @@ func (o *BigCatAllOf) GetKindOk() (*string, bool) {
 
 // HasKind returns a boolean if a field has been set.
 func (o *BigCatAllOf) HasKind() bool {
-	if o != nil && !isNil(o.Kind) {
+	if o != nil && !IsNil(o.Kind) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o BigCatAllOf) MarshalJSON() ([]byte, error) {
 
 func (o BigCatAllOf) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Kind) {
+	if !IsNil(o.Kind) {
 		toSerialize["kind"] = o.Kind
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_capitalization.go b/samples/client/petstore/go/go-petstore/model_capitalization.go
index aef15ffa5b7..5bc3c0cd72f 100644
--- a/samples/client/petstore/go/go-petstore/model_capitalization.go
+++ b/samples/client/petstore/go/go-petstore/model_capitalization.go
@@ -47,7 +47,7 @@ func NewCapitalizationWithDefaults() *Capitalization {
 
 // GetSmallCamel returns the SmallCamel field value if set, zero value otherwise.
 func (o *Capitalization) GetSmallCamel() string {
-	if o == nil || isNil(o.SmallCamel) {
+	if o == nil || IsNil(o.SmallCamel) {
 		var ret string
 		return ret
 	}
@@ -57,7 +57,7 @@ func (o *Capitalization) GetSmallCamel() string {
 // GetSmallCamelOk returns a tuple with the SmallCamel field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetSmallCamelOk() (*string, bool) {
-	if o == nil || isNil(o.SmallCamel) {
+	if o == nil || IsNil(o.SmallCamel) {
 		return nil, false
 	}
 	return o.SmallCamel, true
@@ -65,7 +65,7 @@ func (o *Capitalization) GetSmallCamelOk() (*string, bool) {
 
 // HasSmallCamel returns a boolean if a field has been set.
 func (o *Capitalization) HasSmallCamel() bool {
-	if o != nil && !isNil(o.SmallCamel) {
+	if o != nil && !IsNil(o.SmallCamel) {
 		return true
 	}
 
@@ -79,7 +79,7 @@ func (o *Capitalization) SetSmallCamel(v string) {
 
 // GetCapitalCamel returns the CapitalCamel field value if set, zero value otherwise.
 func (o *Capitalization) GetCapitalCamel() string {
-	if o == nil || isNil(o.CapitalCamel) {
+	if o == nil || IsNil(o.CapitalCamel) {
 		var ret string
 		return ret
 	}
@@ -89,7 +89,7 @@ func (o *Capitalization) GetCapitalCamel() string {
 // GetCapitalCamelOk returns a tuple with the CapitalCamel field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetCapitalCamelOk() (*string, bool) {
-	if o == nil || isNil(o.CapitalCamel) {
+	if o == nil || IsNil(o.CapitalCamel) {
 		return nil, false
 	}
 	return o.CapitalCamel, true
@@ -97,7 +97,7 @@ func (o *Capitalization) GetCapitalCamelOk() (*string, bool) {
 
 // HasCapitalCamel returns a boolean if a field has been set.
 func (o *Capitalization) HasCapitalCamel() bool {
-	if o != nil && !isNil(o.CapitalCamel) {
+	if o != nil && !IsNil(o.CapitalCamel) {
 		return true
 	}
 
@@ -111,7 +111,7 @@ func (o *Capitalization) SetCapitalCamel(v string) {
 
 // GetSmallSnake returns the SmallSnake field value if set, zero value otherwise.
 func (o *Capitalization) GetSmallSnake() string {
-	if o == nil || isNil(o.SmallSnake) {
+	if o == nil || IsNil(o.SmallSnake) {
 		var ret string
 		return ret
 	}
@@ -121,7 +121,7 @@ func (o *Capitalization) GetSmallSnake() string {
 // GetSmallSnakeOk returns a tuple with the SmallSnake field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetSmallSnakeOk() (*string, bool) {
-	if o == nil || isNil(o.SmallSnake) {
+	if o == nil || IsNil(o.SmallSnake) {
 		return nil, false
 	}
 	return o.SmallSnake, true
@@ -129,7 +129,7 @@ func (o *Capitalization) GetSmallSnakeOk() (*string, bool) {
 
 // HasSmallSnake returns a boolean if a field has been set.
 func (o *Capitalization) HasSmallSnake() bool {
-	if o != nil && !isNil(o.SmallSnake) {
+	if o != nil && !IsNil(o.SmallSnake) {
 		return true
 	}
 
@@ -143,7 +143,7 @@ func (o *Capitalization) SetSmallSnake(v string) {
 
 // GetCapitalSnake returns the CapitalSnake field value if set, zero value otherwise.
 func (o *Capitalization) GetCapitalSnake() string {
-	if o == nil || isNil(o.CapitalSnake) {
+	if o == nil || IsNil(o.CapitalSnake) {
 		var ret string
 		return ret
 	}
@@ -153,7 +153,7 @@ func (o *Capitalization) GetCapitalSnake() string {
 // GetCapitalSnakeOk returns a tuple with the CapitalSnake field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetCapitalSnakeOk() (*string, bool) {
-	if o == nil || isNil(o.CapitalSnake) {
+	if o == nil || IsNil(o.CapitalSnake) {
 		return nil, false
 	}
 	return o.CapitalSnake, true
@@ -161,7 +161,7 @@ func (o *Capitalization) GetCapitalSnakeOk() (*string, bool) {
 
 // HasCapitalSnake returns a boolean if a field has been set.
 func (o *Capitalization) HasCapitalSnake() bool {
-	if o != nil && !isNil(o.CapitalSnake) {
+	if o != nil && !IsNil(o.CapitalSnake) {
 		return true
 	}
 
@@ -175,7 +175,7 @@ func (o *Capitalization) SetCapitalSnake(v string) {
 
 // GetSCAETHFlowPoints returns the SCAETHFlowPoints field value if set, zero value otherwise.
 func (o *Capitalization) GetSCAETHFlowPoints() string {
-	if o == nil || isNil(o.SCAETHFlowPoints) {
+	if o == nil || IsNil(o.SCAETHFlowPoints) {
 		var ret string
 		return ret
 	}
@@ -185,7 +185,7 @@ func (o *Capitalization) GetSCAETHFlowPoints() string {
 // GetSCAETHFlowPointsOk returns a tuple with the SCAETHFlowPoints field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetSCAETHFlowPointsOk() (*string, bool) {
-	if o == nil || isNil(o.SCAETHFlowPoints) {
+	if o == nil || IsNil(o.SCAETHFlowPoints) {
 		return nil, false
 	}
 	return o.SCAETHFlowPoints, true
@@ -193,7 +193,7 @@ func (o *Capitalization) GetSCAETHFlowPointsOk() (*string, bool) {
 
 // HasSCAETHFlowPoints returns a boolean if a field has been set.
 func (o *Capitalization) HasSCAETHFlowPoints() bool {
-	if o != nil && !isNil(o.SCAETHFlowPoints) {
+	if o != nil && !IsNil(o.SCAETHFlowPoints) {
 		return true
 	}
 
@@ -207,7 +207,7 @@ func (o *Capitalization) SetSCAETHFlowPoints(v string) {
 
 // GetATT_NAME returns the ATT_NAME field value if set, zero value otherwise.
 func (o *Capitalization) GetATT_NAME() string {
-	if o == nil || isNil(o.ATT_NAME) {
+	if o == nil || IsNil(o.ATT_NAME) {
 		var ret string
 		return ret
 	}
@@ -217,7 +217,7 @@ func (o *Capitalization) GetATT_NAME() string {
 // GetATT_NAMEOk returns a tuple with the ATT_NAME field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetATT_NAMEOk() (*string, bool) {
-	if o == nil || isNil(o.ATT_NAME) {
+	if o == nil || IsNil(o.ATT_NAME) {
 		return nil, false
 	}
 	return o.ATT_NAME, true
@@ -225,7 +225,7 @@ func (o *Capitalization) GetATT_NAMEOk() (*string, bool) {
 
 // HasATT_NAME returns a boolean if a field has been set.
 func (o *Capitalization) HasATT_NAME() bool {
-	if o != nil && !isNil(o.ATT_NAME) {
+	if o != nil && !IsNil(o.ATT_NAME) {
 		return true
 	}
 
@@ -247,22 +247,22 @@ func (o Capitalization) MarshalJSON() ([]byte, error) {
 
 func (o Capitalization) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.SmallCamel) {
+	if !IsNil(o.SmallCamel) {
 		toSerialize["smallCamel"] = o.SmallCamel
 	}
-	if !isNil(o.CapitalCamel) {
+	if !IsNil(o.CapitalCamel) {
 		toSerialize["CapitalCamel"] = o.CapitalCamel
 	}
-	if !isNil(o.SmallSnake) {
+	if !IsNil(o.SmallSnake) {
 		toSerialize["small_Snake"] = o.SmallSnake
 	}
-	if !isNil(o.CapitalSnake) {
+	if !IsNil(o.CapitalSnake) {
 		toSerialize["Capital_Snake"] = o.CapitalSnake
 	}
-	if !isNil(o.SCAETHFlowPoints) {
+	if !IsNil(o.SCAETHFlowPoints) {
 		toSerialize["SCA_ETH_Flow_Points"] = o.SCAETHFlowPoints
 	}
-	if !isNil(o.ATT_NAME) {
+	if !IsNil(o.ATT_NAME) {
 		toSerialize["ATT_NAME"] = o.ATT_NAME
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_cat.go b/samples/client/petstore/go/go-petstore/model_cat.go
index 36ed31dea91..ab791a527ac 100644
--- a/samples/client/petstore/go/go-petstore/model_cat.go
+++ b/samples/client/petstore/go/go-petstore/model_cat.go
@@ -45,7 +45,7 @@ func NewCatWithDefaults() *Cat {
 
 // GetDeclawed returns the Declawed field value if set, zero value otherwise.
 func (o *Cat) GetDeclawed() bool {
-	if o == nil || isNil(o.Declawed) {
+	if o == nil || IsNil(o.Declawed) {
 		var ret bool
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *Cat) GetDeclawed() bool {
 // GetDeclawedOk returns a tuple with the Declawed field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Cat) GetDeclawedOk() (*bool, bool) {
-	if o == nil || isNil(o.Declawed) {
+	if o == nil || IsNil(o.Declawed) {
 		return nil, false
 	}
 	return o.Declawed, true
@@ -63,7 +63,7 @@ func (o *Cat) GetDeclawedOk() (*bool, bool) {
 
 // HasDeclawed returns a boolean if a field has been set.
 func (o *Cat) HasDeclawed() bool {
-	if o != nil && !isNil(o.Declawed) {
+	if o != nil && !IsNil(o.Declawed) {
 		return true
 	}
 
@@ -93,7 +93,7 @@ func (o Cat) ToMap() (map[string]interface{}, error) {
 	if errAnimal != nil {
 		return map[string]interface{}{}, errAnimal
 	}
-	if !isNil(o.Declawed) {
+	if !IsNil(o.Declawed) {
 		toSerialize["declawed"] = o.Declawed
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_cat_all_of.go b/samples/client/petstore/go/go-petstore/model_cat_all_of.go
index 73e0137d340..29c956f3151 100644
--- a/samples/client/petstore/go/go-petstore/model_cat_all_of.go
+++ b/samples/client/petstore/go/go-petstore/model_cat_all_of.go
@@ -41,7 +41,7 @@ func NewCatAllOfWithDefaults() *CatAllOf {
 
 // GetDeclawed returns the Declawed field value if set, zero value otherwise.
 func (o *CatAllOf) GetDeclawed() bool {
-	if o == nil || isNil(o.Declawed) {
+	if o == nil || IsNil(o.Declawed) {
 		var ret bool
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *CatAllOf) GetDeclawed() bool {
 // GetDeclawedOk returns a tuple with the Declawed field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *CatAllOf) GetDeclawedOk() (*bool, bool) {
-	if o == nil || isNil(o.Declawed) {
+	if o == nil || IsNil(o.Declawed) {
 		return nil, false
 	}
 	return o.Declawed, true
@@ -59,7 +59,7 @@ func (o *CatAllOf) GetDeclawedOk() (*bool, bool) {
 
 // HasDeclawed returns a boolean if a field has been set.
 func (o *CatAllOf) HasDeclawed() bool {
-	if o != nil && !isNil(o.Declawed) {
+	if o != nil && !IsNil(o.Declawed) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o CatAllOf) MarshalJSON() ([]byte, error) {
 
 func (o CatAllOf) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Declawed) {
+	if !IsNil(o.Declawed) {
 		toSerialize["declawed"] = o.Declawed
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_category.go b/samples/client/petstore/go/go-petstore/model_category.go
index 3f3971d4230..5275e715064 100644
--- a/samples/client/petstore/go/go-petstore/model_category.go
+++ b/samples/client/petstore/go/go-petstore/model_category.go
@@ -45,7 +45,7 @@ func NewCategoryWithDefaults() *Category {
 
 // GetId returns the Id field value if set, zero value otherwise.
 func (o *Category) GetId() int64 {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		var ret int64
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *Category) GetId() int64 {
 // GetIdOk returns a tuple with the Id field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Category) GetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		return nil, false
 	}
 	return o.Id, true
@@ -63,7 +63,7 @@ func (o *Category) GetIdOk() (*int64, bool) {
 
 // HasId returns a boolean if a field has been set.
 func (o *Category) HasId() bool {
-	if o != nil && !isNil(o.Id) {
+	if o != nil && !IsNil(o.Id) {
 		return true
 	}
 
@@ -109,7 +109,7 @@ func (o Category) MarshalJSON() ([]byte, error) {
 
 func (o Category) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Id) {
+	if !IsNil(o.Id) {
 		toSerialize["id"] = o.Id
 	}
 	toSerialize["name"] = o.Name
diff --git a/samples/client/petstore/go/go-petstore/model_class_model.go b/samples/client/petstore/go/go-petstore/model_class_model.go
index 6c6c7ec2729..23e47a6b692 100644
--- a/samples/client/petstore/go/go-petstore/model_class_model.go
+++ b/samples/client/petstore/go/go-petstore/model_class_model.go
@@ -41,7 +41,7 @@ func NewClassModelWithDefaults() *ClassModel {
 
 // GetClass returns the Class field value if set, zero value otherwise.
 func (o *ClassModel) GetClass() string {
-	if o == nil || isNil(o.Class) {
+	if o == nil || IsNil(o.Class) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *ClassModel) GetClass() string {
 // GetClassOk returns a tuple with the Class field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ClassModel) GetClassOk() (*string, bool) {
-	if o == nil || isNil(o.Class) {
+	if o == nil || IsNil(o.Class) {
 		return nil, false
 	}
 	return o.Class, true
@@ -59,7 +59,7 @@ func (o *ClassModel) GetClassOk() (*string, bool) {
 
 // HasClass returns a boolean if a field has been set.
 func (o *ClassModel) HasClass() bool {
-	if o != nil && !isNil(o.Class) {
+	if o != nil && !IsNil(o.Class) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o ClassModel) MarshalJSON() ([]byte, error) {
 
 func (o ClassModel) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Class) {
+	if !IsNil(o.Class) {
 		toSerialize["_class"] = o.Class
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_client.go b/samples/client/petstore/go/go-petstore/model_client.go
index 88044e6954d..7011509e10c 100644
--- a/samples/client/petstore/go/go-petstore/model_client.go
+++ b/samples/client/petstore/go/go-petstore/model_client.go
@@ -41,7 +41,7 @@ func NewClientWithDefaults() *Client {
 
 // GetClient returns the Client field value if set, zero value otherwise.
 func (o *Client) GetClient() string {
-	if o == nil || isNil(o.Client) {
+	if o == nil || IsNil(o.Client) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *Client) GetClient() string {
 // GetClientOk returns a tuple with the Client field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Client) GetClientOk() (*string, bool) {
-	if o == nil || isNil(o.Client) {
+	if o == nil || IsNil(o.Client) {
 		return nil, false
 	}
 	return o.Client, true
@@ -59,7 +59,7 @@ func (o *Client) GetClientOk() (*string, bool) {
 
 // HasClient returns a boolean if a field has been set.
 func (o *Client) HasClient() bool {
-	if o != nil && !isNil(o.Client) {
+	if o != nil && !IsNil(o.Client) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o Client) MarshalJSON() ([]byte, error) {
 
 func (o Client) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Client) {
+	if !IsNil(o.Client) {
 		toSerialize["client"] = o.Client
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_dog.go b/samples/client/petstore/go/go-petstore/model_dog.go
index f3d6ced5cd2..f0fdbf8b712 100644
--- a/samples/client/petstore/go/go-petstore/model_dog.go
+++ b/samples/client/petstore/go/go-petstore/model_dog.go
@@ -45,7 +45,7 @@ func NewDogWithDefaults() *Dog {
 
 // GetBreed returns the Breed field value if set, zero value otherwise.
 func (o *Dog) GetBreed() string {
-	if o == nil || isNil(o.Breed) {
+	if o == nil || IsNil(o.Breed) {
 		var ret string
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *Dog) GetBreed() string {
 // GetBreedOk returns a tuple with the Breed field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Dog) GetBreedOk() (*string, bool) {
-	if o == nil || isNil(o.Breed) {
+	if o == nil || IsNil(o.Breed) {
 		return nil, false
 	}
 	return o.Breed, true
@@ -63,7 +63,7 @@ func (o *Dog) GetBreedOk() (*string, bool) {
 
 // HasBreed returns a boolean if a field has been set.
 func (o *Dog) HasBreed() bool {
-	if o != nil && !isNil(o.Breed) {
+	if o != nil && !IsNil(o.Breed) {
 		return true
 	}
 
@@ -93,7 +93,7 @@ func (o Dog) ToMap() (map[string]interface{}, error) {
 	if errAnimal != nil {
 		return map[string]interface{}{}, errAnimal
 	}
-	if !isNil(o.Breed) {
+	if !IsNil(o.Breed) {
 		toSerialize["breed"] = o.Breed
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_dog_all_of.go b/samples/client/petstore/go/go-petstore/model_dog_all_of.go
index 3bd9565f4ee..63f065a52d0 100644
--- a/samples/client/petstore/go/go-petstore/model_dog_all_of.go
+++ b/samples/client/petstore/go/go-petstore/model_dog_all_of.go
@@ -41,7 +41,7 @@ func NewDogAllOfWithDefaults() *DogAllOf {
 
 // GetBreed returns the Breed field value if set, zero value otherwise.
 func (o *DogAllOf) GetBreed() string {
-	if o == nil || isNil(o.Breed) {
+	if o == nil || IsNil(o.Breed) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *DogAllOf) GetBreed() string {
 // GetBreedOk returns a tuple with the Breed field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *DogAllOf) GetBreedOk() (*string, bool) {
-	if o == nil || isNil(o.Breed) {
+	if o == nil || IsNil(o.Breed) {
 		return nil, false
 	}
 	return o.Breed, true
@@ -59,7 +59,7 @@ func (o *DogAllOf) GetBreedOk() (*string, bool) {
 
 // HasBreed returns a boolean if a field has been set.
 func (o *DogAllOf) HasBreed() bool {
-	if o != nil && !isNil(o.Breed) {
+	if o != nil && !IsNil(o.Breed) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o DogAllOf) MarshalJSON() ([]byte, error) {
 
 func (o DogAllOf) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Breed) {
+	if !IsNil(o.Breed) {
 		toSerialize["breed"] = o.Breed
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_enum_arrays.go b/samples/client/petstore/go/go-petstore/model_enum_arrays.go
index 9dd784f7309..0342fe0838c 100644
--- a/samples/client/petstore/go/go-petstore/model_enum_arrays.go
+++ b/samples/client/petstore/go/go-petstore/model_enum_arrays.go
@@ -42,7 +42,7 @@ func NewEnumArraysWithDefaults() *EnumArrays {
 
 // GetJustSymbol returns the JustSymbol field value if set, zero value otherwise.
 func (o *EnumArrays) GetJustSymbol() string {
-	if o == nil || isNil(o.JustSymbol) {
+	if o == nil || IsNil(o.JustSymbol) {
 		var ret string
 		return ret
 	}
@@ -52,7 +52,7 @@ func (o *EnumArrays) GetJustSymbol() string {
 // GetJustSymbolOk returns a tuple with the JustSymbol field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumArrays) GetJustSymbolOk() (*string, bool) {
-	if o == nil || isNil(o.JustSymbol) {
+	if o == nil || IsNil(o.JustSymbol) {
 		return nil, false
 	}
 	return o.JustSymbol, true
@@ -60,7 +60,7 @@ func (o *EnumArrays) GetJustSymbolOk() (*string, bool) {
 
 // HasJustSymbol returns a boolean if a field has been set.
 func (o *EnumArrays) HasJustSymbol() bool {
-	if o != nil && !isNil(o.JustSymbol) {
+	if o != nil && !IsNil(o.JustSymbol) {
 		return true
 	}
 
@@ -74,7 +74,7 @@ func (o *EnumArrays) SetJustSymbol(v string) {
 
 // GetArrayEnum returns the ArrayEnum field value if set, zero value otherwise.
 func (o *EnumArrays) GetArrayEnum() []string {
-	if o == nil || isNil(o.ArrayEnum) {
+	if o == nil || IsNil(o.ArrayEnum) {
 		var ret []string
 		return ret
 	}
@@ -84,7 +84,7 @@ func (o *EnumArrays) GetArrayEnum() []string {
 // GetArrayEnumOk returns a tuple with the ArrayEnum field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumArrays) GetArrayEnumOk() ([]string, bool) {
-	if o == nil || isNil(o.ArrayEnum) {
+	if o == nil || IsNil(o.ArrayEnum) {
 		return nil, false
 	}
 	return o.ArrayEnum, true
@@ -92,7 +92,7 @@ func (o *EnumArrays) GetArrayEnumOk() ([]string, bool) {
 
 // HasArrayEnum returns a boolean if a field has been set.
 func (o *EnumArrays) HasArrayEnum() bool {
-	if o != nil && !isNil(o.ArrayEnum) {
+	if o != nil && !IsNil(o.ArrayEnum) {
 		return true
 	}
 
@@ -114,10 +114,10 @@ func (o EnumArrays) MarshalJSON() ([]byte, error) {
 
 func (o EnumArrays) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.JustSymbol) {
+	if !IsNil(o.JustSymbol) {
 		toSerialize["just_symbol"] = o.JustSymbol
 	}
-	if !isNil(o.ArrayEnum) {
+	if !IsNil(o.ArrayEnum) {
 		toSerialize["array_enum"] = o.ArrayEnum
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_enum_test_.go b/samples/client/petstore/go/go-petstore/model_enum_test_.go
index d900de383c6..25114a9f9bb 100644
--- a/samples/client/petstore/go/go-petstore/model_enum_test_.go
+++ b/samples/client/petstore/go/go-petstore/model_enum_test_.go
@@ -46,7 +46,7 @@ func NewEnumTestWithDefaults() *EnumTest {
 
 // GetEnumString returns the EnumString field value if set, zero value otherwise.
 func (o *EnumTest) GetEnumString() string {
-	if o == nil || isNil(o.EnumString) {
+	if o == nil || IsNil(o.EnumString) {
 		var ret string
 		return ret
 	}
@@ -56,7 +56,7 @@ func (o *EnumTest) GetEnumString() string {
 // GetEnumStringOk returns a tuple with the EnumString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumTest) GetEnumStringOk() (*string, bool) {
-	if o == nil || isNil(o.EnumString) {
+	if o == nil || IsNil(o.EnumString) {
 		return nil, false
 	}
 	return o.EnumString, true
@@ -64,7 +64,7 @@ func (o *EnumTest) GetEnumStringOk() (*string, bool) {
 
 // HasEnumString returns a boolean if a field has been set.
 func (o *EnumTest) HasEnumString() bool {
-	if o != nil && !isNil(o.EnumString) {
+	if o != nil && !IsNil(o.EnumString) {
 		return true
 	}
 
@@ -102,7 +102,7 @@ func (o *EnumTest) SetEnumStringRequired(v string) {
 
 // GetEnumInteger returns the EnumInteger field value if set, zero value otherwise.
 func (o *EnumTest) GetEnumInteger() int32 {
-	if o == nil || isNil(o.EnumInteger) {
+	if o == nil || IsNil(o.EnumInteger) {
 		var ret int32
 		return ret
 	}
@@ -112,7 +112,7 @@ func (o *EnumTest) GetEnumInteger() int32 {
 // GetEnumIntegerOk returns a tuple with the EnumInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumTest) GetEnumIntegerOk() (*int32, bool) {
-	if o == nil || isNil(o.EnumInteger) {
+	if o == nil || IsNil(o.EnumInteger) {
 		return nil, false
 	}
 	return o.EnumInteger, true
@@ -120,7 +120,7 @@ func (o *EnumTest) GetEnumIntegerOk() (*int32, bool) {
 
 // HasEnumInteger returns a boolean if a field has been set.
 func (o *EnumTest) HasEnumInteger() bool {
-	if o != nil && !isNil(o.EnumInteger) {
+	if o != nil && !IsNil(o.EnumInteger) {
 		return true
 	}
 
@@ -134,7 +134,7 @@ func (o *EnumTest) SetEnumInteger(v int32) {
 
 // GetEnumNumber returns the EnumNumber field value if set, zero value otherwise.
 func (o *EnumTest) GetEnumNumber() float64 {
-	if o == nil || isNil(o.EnumNumber) {
+	if o == nil || IsNil(o.EnumNumber) {
 		var ret float64
 		return ret
 	}
@@ -144,7 +144,7 @@ func (o *EnumTest) GetEnumNumber() float64 {
 // GetEnumNumberOk returns a tuple with the EnumNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumTest) GetEnumNumberOk() (*float64, bool) {
-	if o == nil || isNil(o.EnumNumber) {
+	if o == nil || IsNil(o.EnumNumber) {
 		return nil, false
 	}
 	return o.EnumNumber, true
@@ -152,7 +152,7 @@ func (o *EnumTest) GetEnumNumberOk() (*float64, bool) {
 
 // HasEnumNumber returns a boolean if a field has been set.
 func (o *EnumTest) HasEnumNumber() bool {
-	if o != nil && !isNil(o.EnumNumber) {
+	if o != nil && !IsNil(o.EnumNumber) {
 		return true
 	}
 
@@ -166,7 +166,7 @@ func (o *EnumTest) SetEnumNumber(v float64) {
 
 // GetOuterEnum returns the OuterEnum field value if set, zero value otherwise.
 func (o *EnumTest) GetOuterEnum() OuterEnum {
-	if o == nil || isNil(o.OuterEnum) {
+	if o == nil || IsNil(o.OuterEnum) {
 		var ret OuterEnum
 		return ret
 	}
@@ -176,7 +176,7 @@ func (o *EnumTest) GetOuterEnum() OuterEnum {
 // GetOuterEnumOk returns a tuple with the OuterEnum field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumTest) GetOuterEnumOk() (*OuterEnum, bool) {
-	if o == nil || isNil(o.OuterEnum) {
+	if o == nil || IsNil(o.OuterEnum) {
 		return nil, false
 	}
 	return o.OuterEnum, true
@@ -184,7 +184,7 @@ func (o *EnumTest) GetOuterEnumOk() (*OuterEnum, bool) {
 
 // HasOuterEnum returns a boolean if a field has been set.
 func (o *EnumTest) HasOuterEnum() bool {
-	if o != nil && !isNil(o.OuterEnum) {
+	if o != nil && !IsNil(o.OuterEnum) {
 		return true
 	}
 
@@ -206,17 +206,17 @@ func (o EnumTest) MarshalJSON() ([]byte, error) {
 
 func (o EnumTest) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.EnumString) {
+	if !IsNil(o.EnumString) {
 		toSerialize["enum_string"] = o.EnumString
 	}
 	toSerialize["enum_string_required"] = o.EnumStringRequired
-	if !isNil(o.EnumInteger) {
+	if !IsNil(o.EnumInteger) {
 		toSerialize["enum_integer"] = o.EnumInteger
 	}
-	if !isNil(o.EnumNumber) {
+	if !IsNil(o.EnumNumber) {
 		toSerialize["enum_number"] = o.EnumNumber
 	}
-	if !isNil(o.OuterEnum) {
+	if !IsNil(o.OuterEnum) {
 		toSerialize["outerEnum"] = o.OuterEnum
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_file.go b/samples/client/petstore/go/go-petstore/model_file.go
index 1838c23c716..62847b33159 100644
--- a/samples/client/petstore/go/go-petstore/model_file.go
+++ b/samples/client/petstore/go/go-petstore/model_file.go
@@ -42,7 +42,7 @@ func NewFileWithDefaults() *File {
 
 // GetSourceURI returns the SourceURI field value if set, zero value otherwise.
 func (o *File) GetSourceURI() string {
-	if o == nil || isNil(o.SourceURI) {
+	if o == nil || IsNil(o.SourceURI) {
 		var ret string
 		return ret
 	}
@@ -52,7 +52,7 @@ func (o *File) GetSourceURI() string {
 // GetSourceURIOk returns a tuple with the SourceURI field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *File) GetSourceURIOk() (*string, bool) {
-	if o == nil || isNil(o.SourceURI) {
+	if o == nil || IsNil(o.SourceURI) {
 		return nil, false
 	}
 	return o.SourceURI, true
@@ -60,7 +60,7 @@ func (o *File) GetSourceURIOk() (*string, bool) {
 
 // HasSourceURI returns a boolean if a field has been set.
 func (o *File) HasSourceURI() bool {
-	if o != nil && !isNil(o.SourceURI) {
+	if o != nil && !IsNil(o.SourceURI) {
 		return true
 	}
 
@@ -82,7 +82,7 @@ func (o File) MarshalJSON() ([]byte, error) {
 
 func (o File) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.SourceURI) {
+	if !IsNil(o.SourceURI) {
 		toSerialize["sourceURI"] = o.SourceURI
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_file_schema_test_class.go b/samples/client/petstore/go/go-petstore/model_file_schema_test_class.go
index 3b7a053dd8d..6d9ce70ca04 100644
--- a/samples/client/petstore/go/go-petstore/model_file_schema_test_class.go
+++ b/samples/client/petstore/go/go-petstore/model_file_schema_test_class.go
@@ -42,7 +42,7 @@ func NewFileSchemaTestClassWithDefaults() *FileSchemaTestClass {
 
 // GetFile returns the File field value if set, zero value otherwise.
 func (o *FileSchemaTestClass) GetFile() File {
-	if o == nil || isNil(o.File) {
+	if o == nil || IsNil(o.File) {
 		var ret File
 		return ret
 	}
@@ -52,7 +52,7 @@ func (o *FileSchemaTestClass) GetFile() File {
 // GetFileOk returns a tuple with the File field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FileSchemaTestClass) GetFileOk() (*File, bool) {
-	if o == nil || isNil(o.File) {
+	if o == nil || IsNil(o.File) {
 		return nil, false
 	}
 	return o.File, true
@@ -60,7 +60,7 @@ func (o *FileSchemaTestClass) GetFileOk() (*File, bool) {
 
 // HasFile returns a boolean if a field has been set.
 func (o *FileSchemaTestClass) HasFile() bool {
-	if o != nil && !isNil(o.File) {
+	if o != nil && !IsNil(o.File) {
 		return true
 	}
 
@@ -74,7 +74,7 @@ func (o *FileSchemaTestClass) SetFile(v File) {
 
 // GetFiles returns the Files field value if set, zero value otherwise.
 func (o *FileSchemaTestClass) GetFiles() []File {
-	if o == nil || isNil(o.Files) {
+	if o == nil || IsNil(o.Files) {
 		var ret []File
 		return ret
 	}
@@ -84,7 +84,7 @@ func (o *FileSchemaTestClass) GetFiles() []File {
 // GetFilesOk returns a tuple with the Files field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FileSchemaTestClass) GetFilesOk() ([]File, bool) {
-	if o == nil || isNil(o.Files) {
+	if o == nil || IsNil(o.Files) {
 		return nil, false
 	}
 	return o.Files, true
@@ -92,7 +92,7 @@ func (o *FileSchemaTestClass) GetFilesOk() ([]File, bool) {
 
 // HasFiles returns a boolean if a field has been set.
 func (o *FileSchemaTestClass) HasFiles() bool {
-	if o != nil && !isNil(o.Files) {
+	if o != nil && !IsNil(o.Files) {
 		return true
 	}
 
@@ -114,10 +114,10 @@ func (o FileSchemaTestClass) MarshalJSON() ([]byte, error) {
 
 func (o FileSchemaTestClass) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.File) {
+	if !IsNil(o.File) {
 		toSerialize["file"] = o.File
 	}
-	if !isNil(o.Files) {
+	if !IsNil(o.Files) {
 		toSerialize["files"] = o.Files
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_format_test_.go b/samples/client/petstore/go/go-petstore/model_format_test_.go
index 0cfe962744c..233c531076b 100644
--- a/samples/client/petstore/go/go-petstore/model_format_test_.go
+++ b/samples/client/petstore/go/go-petstore/model_format_test_.go
@@ -60,7 +60,7 @@ func NewFormatTestWithDefaults() *FormatTest {
 
 // GetInteger returns the Integer field value if set, zero value otherwise.
 func (o *FormatTest) GetInteger() int32 {
-	if o == nil || isNil(o.Integer) {
+	if o == nil || IsNil(o.Integer) {
 		var ret int32
 		return ret
 	}
@@ -70,7 +70,7 @@ func (o *FormatTest) GetInteger() int32 {
 // GetIntegerOk returns a tuple with the Integer field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetIntegerOk() (*int32, bool) {
-	if o == nil || isNil(o.Integer) {
+	if o == nil || IsNil(o.Integer) {
 		return nil, false
 	}
 	return o.Integer, true
@@ -78,7 +78,7 @@ func (o *FormatTest) GetIntegerOk() (*int32, bool) {
 
 // HasInteger returns a boolean if a field has been set.
 func (o *FormatTest) HasInteger() bool {
-	if o != nil && !isNil(o.Integer) {
+	if o != nil && !IsNil(o.Integer) {
 		return true
 	}
 
@@ -92,7 +92,7 @@ func (o *FormatTest) SetInteger(v int32) {
 
 // GetInt32 returns the Int32 field value if set, zero value otherwise.
 func (o *FormatTest) GetInt32() int32 {
-	if o == nil || isNil(o.Int32) {
+	if o == nil || IsNil(o.Int32) {
 		var ret int32
 		return ret
 	}
@@ -102,7 +102,7 @@ func (o *FormatTest) GetInt32() int32 {
 // GetInt32Ok returns a tuple with the Int32 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetInt32Ok() (*int32, bool) {
-	if o == nil || isNil(o.Int32) {
+	if o == nil || IsNil(o.Int32) {
 		return nil, false
 	}
 	return o.Int32, true
@@ -110,7 +110,7 @@ func (o *FormatTest) GetInt32Ok() (*int32, bool) {
 
 // HasInt32 returns a boolean if a field has been set.
 func (o *FormatTest) HasInt32() bool {
-	if o != nil && !isNil(o.Int32) {
+	if o != nil && !IsNil(o.Int32) {
 		return true
 	}
 
@@ -124,7 +124,7 @@ func (o *FormatTest) SetInt32(v int32) {
 
 // GetInt64 returns the Int64 field value if set, zero value otherwise.
 func (o *FormatTest) GetInt64() int64 {
-	if o == nil || isNil(o.Int64) {
+	if o == nil || IsNil(o.Int64) {
 		var ret int64
 		return ret
 	}
@@ -134,7 +134,7 @@ func (o *FormatTest) GetInt64() int64 {
 // GetInt64Ok returns a tuple with the Int64 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetInt64Ok() (*int64, bool) {
-	if o == nil || isNil(o.Int64) {
+	if o == nil || IsNil(o.Int64) {
 		return nil, false
 	}
 	return o.Int64, true
@@ -142,7 +142,7 @@ func (o *FormatTest) GetInt64Ok() (*int64, bool) {
 
 // HasInt64 returns a boolean if a field has been set.
 func (o *FormatTest) HasInt64() bool {
-	if o != nil && !isNil(o.Int64) {
+	if o != nil && !IsNil(o.Int64) {
 		return true
 	}
 
@@ -180,7 +180,7 @@ func (o *FormatTest) SetNumber(v float32) {
 
 // GetFloat returns the Float field value if set, zero value otherwise.
 func (o *FormatTest) GetFloat() float32 {
-	if o == nil || isNil(o.Float) {
+	if o == nil || IsNil(o.Float) {
 		var ret float32
 		return ret
 	}
@@ -190,7 +190,7 @@ func (o *FormatTest) GetFloat() float32 {
 // GetFloatOk returns a tuple with the Float field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetFloatOk() (*float32, bool) {
-	if o == nil || isNil(o.Float) {
+	if o == nil || IsNil(o.Float) {
 		return nil, false
 	}
 	return o.Float, true
@@ -198,7 +198,7 @@ func (o *FormatTest) GetFloatOk() (*float32, bool) {
 
 // HasFloat returns a boolean if a field has been set.
 func (o *FormatTest) HasFloat() bool {
-	if o != nil && !isNil(o.Float) {
+	if o != nil && !IsNil(o.Float) {
 		return true
 	}
 
@@ -212,7 +212,7 @@ func (o *FormatTest) SetFloat(v float32) {
 
 // GetDouble returns the Double field value if set, zero value otherwise.
 func (o *FormatTest) GetDouble() float64 {
-	if o == nil || isNil(o.Double) {
+	if o == nil || IsNil(o.Double) {
 		var ret float64
 		return ret
 	}
@@ -222,7 +222,7 @@ func (o *FormatTest) GetDouble() float64 {
 // GetDoubleOk returns a tuple with the Double field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetDoubleOk() (*float64, bool) {
-	if o == nil || isNil(o.Double) {
+	if o == nil || IsNil(o.Double) {
 		return nil, false
 	}
 	return o.Double, true
@@ -230,7 +230,7 @@ func (o *FormatTest) GetDoubleOk() (*float64, bool) {
 
 // HasDouble returns a boolean if a field has been set.
 func (o *FormatTest) HasDouble() bool {
-	if o != nil && !isNil(o.Double) {
+	if o != nil && !IsNil(o.Double) {
 		return true
 	}
 
@@ -244,7 +244,7 @@ func (o *FormatTest) SetDouble(v float64) {
 
 // GetString returns the String field value if set, zero value otherwise.
 func (o *FormatTest) GetString() string {
-	if o == nil || isNil(o.String) {
+	if o == nil || IsNil(o.String) {
 		var ret string
 		return ret
 	}
@@ -254,7 +254,7 @@ func (o *FormatTest) GetString() string {
 // GetStringOk returns a tuple with the String field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetStringOk() (*string, bool) {
-	if o == nil || isNil(o.String) {
+	if o == nil || IsNil(o.String) {
 		return nil, false
 	}
 	return o.String, true
@@ -262,7 +262,7 @@ func (o *FormatTest) GetStringOk() (*string, bool) {
 
 // HasString returns a boolean if a field has been set.
 func (o *FormatTest) HasString() bool {
-	if o != nil && !isNil(o.String) {
+	if o != nil && !IsNil(o.String) {
 		return true
 	}
 
@@ -300,7 +300,7 @@ func (o *FormatTest) SetByte(v string) {
 
 // GetBinary returns the Binary field value if set, zero value otherwise.
 func (o *FormatTest) GetBinary() *os.File {
-	if o == nil || isNil(o.Binary) {
+	if o == nil || IsNil(o.Binary) {
 		var ret *os.File
 		return ret
 	}
@@ -310,7 +310,7 @@ func (o *FormatTest) GetBinary() *os.File {
 // GetBinaryOk returns a tuple with the Binary field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetBinaryOk() (**os.File, bool) {
-	if o == nil || isNil(o.Binary) {
+	if o == nil || IsNil(o.Binary) {
 		return nil, false
 	}
 	return o.Binary, true
@@ -318,7 +318,7 @@ func (o *FormatTest) GetBinaryOk() (**os.File, bool) {
 
 // HasBinary returns a boolean if a field has been set.
 func (o *FormatTest) HasBinary() bool {
-	if o != nil && !isNil(o.Binary) {
+	if o != nil && !IsNil(o.Binary) {
 		return true
 	}
 
@@ -356,7 +356,7 @@ func (o *FormatTest) SetDate(v string) {
 
 // GetDateTime returns the DateTime field value if set, zero value otherwise.
 func (o *FormatTest) GetDateTime() time.Time {
-	if o == nil || isNil(o.DateTime) {
+	if o == nil || IsNil(o.DateTime) {
 		var ret time.Time
 		return ret
 	}
@@ -366,7 +366,7 @@ func (o *FormatTest) GetDateTime() time.Time {
 // GetDateTimeOk returns a tuple with the DateTime field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetDateTimeOk() (*time.Time, bool) {
-	if o == nil || isNil(o.DateTime) {
+	if o == nil || IsNil(o.DateTime) {
 		return nil, false
 	}
 	return o.DateTime, true
@@ -374,7 +374,7 @@ func (o *FormatTest) GetDateTimeOk() (*time.Time, bool) {
 
 // HasDateTime returns a boolean if a field has been set.
 func (o *FormatTest) HasDateTime() bool {
-	if o != nil && !isNil(o.DateTime) {
+	if o != nil && !IsNil(o.DateTime) {
 		return true
 	}
 
@@ -388,7 +388,7 @@ func (o *FormatTest) SetDateTime(v time.Time) {
 
 // GetUuid returns the Uuid field value if set, zero value otherwise.
 func (o *FormatTest) GetUuid() string {
-	if o == nil || isNil(o.Uuid) {
+	if o == nil || IsNil(o.Uuid) {
 		var ret string
 		return ret
 	}
@@ -398,7 +398,7 @@ func (o *FormatTest) GetUuid() string {
 // GetUuidOk returns a tuple with the Uuid field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetUuidOk() (*string, bool) {
-	if o == nil || isNil(o.Uuid) {
+	if o == nil || IsNil(o.Uuid) {
 		return nil, false
 	}
 	return o.Uuid, true
@@ -406,7 +406,7 @@ func (o *FormatTest) GetUuidOk() (*string, bool) {
 
 // HasUuid returns a boolean if a field has been set.
 func (o *FormatTest) HasUuid() bool {
-	if o != nil && !isNil(o.Uuid) {
+	if o != nil && !IsNil(o.Uuid) {
 		return true
 	}
 
@@ -444,7 +444,7 @@ func (o *FormatTest) SetPassword(v string) {
 
 // GetBigDecimal returns the BigDecimal field value if set, zero value otherwise.
 func (o *FormatTest) GetBigDecimal() float64 {
-	if o == nil || isNil(o.BigDecimal) {
+	if o == nil || IsNil(o.BigDecimal) {
 		var ret float64
 		return ret
 	}
@@ -454,7 +454,7 @@ func (o *FormatTest) GetBigDecimal() float64 {
 // GetBigDecimalOk returns a tuple with the BigDecimal field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetBigDecimalOk() (*float64, bool) {
-	if o == nil || isNil(o.BigDecimal) {
+	if o == nil || IsNil(o.BigDecimal) {
 		return nil, false
 	}
 	return o.BigDecimal, true
@@ -462,7 +462,7 @@ func (o *FormatTest) GetBigDecimalOk() (*float64, bool) {
 
 // HasBigDecimal returns a boolean if a field has been set.
 func (o *FormatTest) HasBigDecimal() bool {
-	if o != nil && !isNil(o.BigDecimal) {
+	if o != nil && !IsNil(o.BigDecimal) {
 		return true
 	}
 
@@ -484,38 +484,38 @@ func (o FormatTest) MarshalJSON() ([]byte, error) {
 
 func (o FormatTest) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Integer) {
+	if !IsNil(o.Integer) {
 		toSerialize["integer"] = o.Integer
 	}
-	if !isNil(o.Int32) {
+	if !IsNil(o.Int32) {
 		toSerialize["int32"] = o.Int32
 	}
-	if !isNil(o.Int64) {
+	if !IsNil(o.Int64) {
 		toSerialize["int64"] = o.Int64
 	}
 	toSerialize["number"] = o.Number
-	if !isNil(o.Float) {
+	if !IsNil(o.Float) {
 		toSerialize["float"] = o.Float
 	}
-	if !isNil(o.Double) {
+	if !IsNil(o.Double) {
 		toSerialize["double"] = o.Double
 	}
-	if !isNil(o.String) {
+	if !IsNil(o.String) {
 		toSerialize["string"] = o.String
 	}
 	toSerialize["byte"] = o.Byte
-	if !isNil(o.Binary) {
+	if !IsNil(o.Binary) {
 		toSerialize["binary"] = o.Binary
 	}
 	toSerialize["date"] = o.Date
-	if !isNil(o.DateTime) {
+	if !IsNil(o.DateTime) {
 		toSerialize["dateTime"] = o.DateTime
 	}
-	if !isNil(o.Uuid) {
+	if !IsNil(o.Uuid) {
 		toSerialize["uuid"] = o.Uuid
 	}
 	toSerialize["password"] = o.Password
-	if !isNil(o.BigDecimal) {
+	if !IsNil(o.BigDecimal) {
 		toSerialize["BigDecimal"] = o.BigDecimal
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_has_only_read_only.go b/samples/client/petstore/go/go-petstore/model_has_only_read_only.go
index 1f4cbff9154..7fd71a40d34 100644
--- a/samples/client/petstore/go/go-petstore/model_has_only_read_only.go
+++ b/samples/client/petstore/go/go-petstore/model_has_only_read_only.go
@@ -42,7 +42,7 @@ func NewHasOnlyReadOnlyWithDefaults() *HasOnlyReadOnly {
 
 // GetBar returns the Bar field value if set, zero value otherwise.
 func (o *HasOnlyReadOnly) GetBar() string {
-	if o == nil || isNil(o.Bar) {
+	if o == nil || IsNil(o.Bar) {
 		var ret string
 		return ret
 	}
@@ -52,7 +52,7 @@ func (o *HasOnlyReadOnly) GetBar() string {
 // GetBarOk returns a tuple with the Bar field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *HasOnlyReadOnly) GetBarOk() (*string, bool) {
-	if o == nil || isNil(o.Bar) {
+	if o == nil || IsNil(o.Bar) {
 		return nil, false
 	}
 	return o.Bar, true
@@ -60,7 +60,7 @@ func (o *HasOnlyReadOnly) GetBarOk() (*string, bool) {
 
 // HasBar returns a boolean if a field has been set.
 func (o *HasOnlyReadOnly) HasBar() bool {
-	if o != nil && !isNil(o.Bar) {
+	if o != nil && !IsNil(o.Bar) {
 		return true
 	}
 
@@ -74,7 +74,7 @@ func (o *HasOnlyReadOnly) SetBar(v string) {
 
 // GetFoo returns the Foo field value if set, zero value otherwise.
 func (o *HasOnlyReadOnly) GetFoo() string {
-	if o == nil || isNil(o.Foo) {
+	if o == nil || IsNil(o.Foo) {
 		var ret string
 		return ret
 	}
@@ -84,7 +84,7 @@ func (o *HasOnlyReadOnly) GetFoo() string {
 // GetFooOk returns a tuple with the Foo field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *HasOnlyReadOnly) GetFooOk() (*string, bool) {
-	if o == nil || isNil(o.Foo) {
+	if o == nil || IsNil(o.Foo) {
 		return nil, false
 	}
 	return o.Foo, true
@@ -92,7 +92,7 @@ func (o *HasOnlyReadOnly) GetFooOk() (*string, bool) {
 
 // HasFoo returns a boolean if a field has been set.
 func (o *HasOnlyReadOnly) HasFoo() bool {
-	if o != nil && !isNil(o.Foo) {
+	if o != nil && !IsNil(o.Foo) {
 		return true
 	}
 
diff --git a/samples/client/petstore/go/go-petstore/model_list.go b/samples/client/petstore/go/go-petstore/model_list.go
index 6ac1ff3ba47..db218859da0 100644
--- a/samples/client/petstore/go/go-petstore/model_list.go
+++ b/samples/client/petstore/go/go-petstore/model_list.go
@@ -41,7 +41,7 @@ func NewListWithDefaults() *List {
 
 // GetVar123List returns the Var123List field value if set, zero value otherwise.
 func (o *List) GetVar123List() string {
-	if o == nil || isNil(o.Var123List) {
+	if o == nil || IsNil(o.Var123List) {
 		var ret string
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *List) GetVar123List() string {
 // GetVar123ListOk returns a tuple with the Var123List field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *List) GetVar123ListOk() (*string, bool) {
-	if o == nil || isNil(o.Var123List) {
+	if o == nil || IsNil(o.Var123List) {
 		return nil, false
 	}
 	return o.Var123List, true
@@ -59,7 +59,7 @@ func (o *List) GetVar123ListOk() (*string, bool) {
 
 // HasVar123List returns a boolean if a field has been set.
 func (o *List) HasVar123List() bool {
-	if o != nil && !isNil(o.Var123List) {
+	if o != nil && !IsNil(o.Var123List) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o List) MarshalJSON() ([]byte, error) {
 
 func (o List) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Var123List) {
+	if !IsNil(o.Var123List) {
 		toSerialize["123-list"] = o.Var123List
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_map_test_.go b/samples/client/petstore/go/go-petstore/model_map_test_.go
index a9eb3d11966..78ca3949a67 100644
--- a/samples/client/petstore/go/go-petstore/model_map_test_.go
+++ b/samples/client/petstore/go/go-petstore/model_map_test_.go
@@ -44,7 +44,7 @@ func NewMapTestWithDefaults() *MapTest {
 
 // GetMapMapOfString returns the MapMapOfString field value if set, zero value otherwise.
 func (o *MapTest) GetMapMapOfString() map[string]map[string]string {
-	if o == nil || isNil(o.MapMapOfString) {
+	if o == nil || IsNil(o.MapMapOfString) {
 		var ret map[string]map[string]string
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *MapTest) GetMapMapOfString() map[string]map[string]string {
 // GetMapMapOfStringOk returns a tuple with the MapMapOfString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MapTest) GetMapMapOfStringOk() (*map[string]map[string]string, bool) {
-	if o == nil || isNil(o.MapMapOfString) {
+	if o == nil || IsNil(o.MapMapOfString) {
 		return nil, false
 	}
 	return o.MapMapOfString, true
@@ -62,7 +62,7 @@ func (o *MapTest) GetMapMapOfStringOk() (*map[string]map[string]string, bool) {
 
 // HasMapMapOfString returns a boolean if a field has been set.
 func (o *MapTest) HasMapMapOfString() bool {
-	if o != nil && !isNil(o.MapMapOfString) {
+	if o != nil && !IsNil(o.MapMapOfString) {
 		return true
 	}
 
@@ -76,7 +76,7 @@ func (o *MapTest) SetMapMapOfString(v map[string]map[string]string) {
 
 // GetMapOfEnumString returns the MapOfEnumString field value if set, zero value otherwise.
 func (o *MapTest) GetMapOfEnumString() map[string]string {
-	if o == nil || isNil(o.MapOfEnumString) {
+	if o == nil || IsNil(o.MapOfEnumString) {
 		var ret map[string]string
 		return ret
 	}
@@ -86,7 +86,7 @@ func (o *MapTest) GetMapOfEnumString() map[string]string {
 // GetMapOfEnumStringOk returns a tuple with the MapOfEnumString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MapTest) GetMapOfEnumStringOk() (*map[string]string, bool) {
-	if o == nil || isNil(o.MapOfEnumString) {
+	if o == nil || IsNil(o.MapOfEnumString) {
 		return nil, false
 	}
 	return o.MapOfEnumString, true
@@ -94,7 +94,7 @@ func (o *MapTest) GetMapOfEnumStringOk() (*map[string]string, bool) {
 
 // HasMapOfEnumString returns a boolean if a field has been set.
 func (o *MapTest) HasMapOfEnumString() bool {
-	if o != nil && !isNil(o.MapOfEnumString) {
+	if o != nil && !IsNil(o.MapOfEnumString) {
 		return true
 	}
 
@@ -108,7 +108,7 @@ func (o *MapTest) SetMapOfEnumString(v map[string]string) {
 
 // GetDirectMap returns the DirectMap field value if set, zero value otherwise.
 func (o *MapTest) GetDirectMap() map[string]bool {
-	if o == nil || isNil(o.DirectMap) {
+	if o == nil || IsNil(o.DirectMap) {
 		var ret map[string]bool
 		return ret
 	}
@@ -118,7 +118,7 @@ func (o *MapTest) GetDirectMap() map[string]bool {
 // GetDirectMapOk returns a tuple with the DirectMap field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MapTest) GetDirectMapOk() (*map[string]bool, bool) {
-	if o == nil || isNil(o.DirectMap) {
+	if o == nil || IsNil(o.DirectMap) {
 		return nil, false
 	}
 	return o.DirectMap, true
@@ -126,7 +126,7 @@ func (o *MapTest) GetDirectMapOk() (*map[string]bool, bool) {
 
 // HasDirectMap returns a boolean if a field has been set.
 func (o *MapTest) HasDirectMap() bool {
-	if o != nil && !isNil(o.DirectMap) {
+	if o != nil && !IsNil(o.DirectMap) {
 		return true
 	}
 
@@ -140,7 +140,7 @@ func (o *MapTest) SetDirectMap(v map[string]bool) {
 
 // GetIndirectMap returns the IndirectMap field value if set, zero value otherwise.
 func (o *MapTest) GetIndirectMap() map[string]bool {
-	if o == nil || isNil(o.IndirectMap) {
+	if o == nil || IsNil(o.IndirectMap) {
 		var ret map[string]bool
 		return ret
 	}
@@ -150,7 +150,7 @@ func (o *MapTest) GetIndirectMap() map[string]bool {
 // GetIndirectMapOk returns a tuple with the IndirectMap field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MapTest) GetIndirectMapOk() (*map[string]bool, bool) {
-	if o == nil || isNil(o.IndirectMap) {
+	if o == nil || IsNil(o.IndirectMap) {
 		return nil, false
 	}
 	return o.IndirectMap, true
@@ -158,7 +158,7 @@ func (o *MapTest) GetIndirectMapOk() (*map[string]bool, bool) {
 
 // HasIndirectMap returns a boolean if a field has been set.
 func (o *MapTest) HasIndirectMap() bool {
-	if o != nil && !isNil(o.IndirectMap) {
+	if o != nil && !IsNil(o.IndirectMap) {
 		return true
 	}
 
@@ -180,16 +180,16 @@ func (o MapTest) MarshalJSON() ([]byte, error) {
 
 func (o MapTest) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.MapMapOfString) {
+	if !IsNil(o.MapMapOfString) {
 		toSerialize["map_map_of_string"] = o.MapMapOfString
 	}
-	if !isNil(o.MapOfEnumString) {
+	if !IsNil(o.MapOfEnumString) {
 		toSerialize["map_of_enum_string"] = o.MapOfEnumString
 	}
-	if !isNil(o.DirectMap) {
+	if !IsNil(o.DirectMap) {
 		toSerialize["direct_map"] = o.DirectMap
 	}
-	if !isNil(o.IndirectMap) {
+	if !IsNil(o.IndirectMap) {
 		toSerialize["indirect_map"] = o.IndirectMap
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_mixed_properties_and_additional_properties_class.go b/samples/client/petstore/go/go-petstore/model_mixed_properties_and_additional_properties_class.go
index d73df37de7f..e3baadf91b2 100644
--- a/samples/client/petstore/go/go-petstore/model_mixed_properties_and_additional_properties_class.go
+++ b/samples/client/petstore/go/go-petstore/model_mixed_properties_and_additional_properties_class.go
@@ -44,7 +44,7 @@ func NewMixedPropertiesAndAdditionalPropertiesClassWithDefaults() *MixedProperti
 
 // GetUuid returns the Uuid field value if set, zero value otherwise.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetUuid() string {
-	if o == nil || isNil(o.Uuid) {
+	if o == nil || IsNil(o.Uuid) {
 		var ret string
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetUuid() string {
 // GetUuidOk returns a tuple with the Uuid field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetUuidOk() (*string, bool) {
-	if o == nil || isNil(o.Uuid) {
+	if o == nil || IsNil(o.Uuid) {
 		return nil, false
 	}
 	return o.Uuid, true
@@ -62,7 +62,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetUuidOk() (*string, bool
 
 // HasUuid returns a boolean if a field has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) HasUuid() bool {
-	if o != nil && !isNil(o.Uuid) {
+	if o != nil && !IsNil(o.Uuid) {
 		return true
 	}
 
@@ -76,7 +76,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) SetUuid(v string) {
 
 // GetDateTime returns the DateTime field value if set, zero value otherwise.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetDateTime() time.Time {
-	if o == nil || isNil(o.DateTime) {
+	if o == nil || IsNil(o.DateTime) {
 		var ret time.Time
 		return ret
 	}
@@ -86,7 +86,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetDateTime() time.Time {
 // GetDateTimeOk returns a tuple with the DateTime field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetDateTimeOk() (*time.Time, bool) {
-	if o == nil || isNil(o.DateTime) {
+	if o == nil || IsNil(o.DateTime) {
 		return nil, false
 	}
 	return o.DateTime, true
@@ -94,7 +94,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetDateTimeOk() (*time.Tim
 
 // HasDateTime returns a boolean if a field has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) HasDateTime() bool {
-	if o != nil && !isNil(o.DateTime) {
+	if o != nil && !IsNil(o.DateTime) {
 		return true
 	}
 
@@ -108,7 +108,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) SetDateTime(v time.Time) {
 
 // GetMap returns the Map field value if set, zero value otherwise.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetMap() map[string]Animal {
-	if o == nil || isNil(o.Map) {
+	if o == nil || IsNil(o.Map) {
 		var ret map[string]Animal
 		return ret
 	}
@@ -118,7 +118,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetMap() map[string]Animal
 // GetMapOk returns a tuple with the Map field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetMapOk() (*map[string]Animal, bool) {
-	if o == nil || isNil(o.Map) {
+	if o == nil || IsNil(o.Map) {
 		return nil, false
 	}
 	return o.Map, true
@@ -126,7 +126,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetMapOk() (*map[string]An
 
 // HasMap returns a boolean if a field has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) HasMap() bool {
-	if o != nil && !isNil(o.Map) {
+	if o != nil && !IsNil(o.Map) {
 		return true
 	}
 
@@ -148,13 +148,13 @@ func (o MixedPropertiesAndAdditionalPropertiesClass) MarshalJSON() ([]byte, erro
 
 func (o MixedPropertiesAndAdditionalPropertiesClass) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Uuid) {
+	if !IsNil(o.Uuid) {
 		toSerialize["uuid"] = o.Uuid
 	}
-	if !isNil(o.DateTime) {
+	if !IsNil(o.DateTime) {
 		toSerialize["dateTime"] = o.DateTime
 	}
-	if !isNil(o.Map) {
+	if !IsNil(o.Map) {
 		toSerialize["map"] = o.Map
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_name.go b/samples/client/petstore/go/go-petstore/model_name.go
index cca94e9d64b..76b59209ac4 100644
--- a/samples/client/petstore/go/go-petstore/model_name.go
+++ b/samples/client/petstore/go/go-petstore/model_name.go
@@ -69,7 +69,7 @@ func (o *Name) SetName(v int32) {
 
 // GetSnakeCase returns the SnakeCase field value if set, zero value otherwise.
 func (o *Name) GetSnakeCase() int32 {
-	if o == nil || isNil(o.SnakeCase) {
+	if o == nil || IsNil(o.SnakeCase) {
 		var ret int32
 		return ret
 	}
@@ -79,7 +79,7 @@ func (o *Name) GetSnakeCase() int32 {
 // GetSnakeCaseOk returns a tuple with the SnakeCase field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Name) GetSnakeCaseOk() (*int32, bool) {
-	if o == nil || isNil(o.SnakeCase) {
+	if o == nil || IsNil(o.SnakeCase) {
 		return nil, false
 	}
 	return o.SnakeCase, true
@@ -87,7 +87,7 @@ func (o *Name) GetSnakeCaseOk() (*int32, bool) {
 
 // HasSnakeCase returns a boolean if a field has been set.
 func (o *Name) HasSnakeCase() bool {
-	if o != nil && !isNil(o.SnakeCase) {
+	if o != nil && !IsNil(o.SnakeCase) {
 		return true
 	}
 
@@ -101,7 +101,7 @@ func (o *Name) SetSnakeCase(v int32) {
 
 // GetProperty returns the Property field value if set, zero value otherwise.
 func (o *Name) GetProperty() string {
-	if o == nil || isNil(o.Property) {
+	if o == nil || IsNil(o.Property) {
 		var ret string
 		return ret
 	}
@@ -111,7 +111,7 @@ func (o *Name) GetProperty() string {
 // GetPropertyOk returns a tuple with the Property field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Name) GetPropertyOk() (*string, bool) {
-	if o == nil || isNil(o.Property) {
+	if o == nil || IsNil(o.Property) {
 		return nil, false
 	}
 	return o.Property, true
@@ -119,7 +119,7 @@ func (o *Name) GetPropertyOk() (*string, bool) {
 
 // HasProperty returns a boolean if a field has been set.
 func (o *Name) HasProperty() bool {
-	if o != nil && !isNil(o.Property) {
+	if o != nil && !IsNil(o.Property) {
 		return true
 	}
 
@@ -133,7 +133,7 @@ func (o *Name) SetProperty(v string) {
 
 // GetVar123Number returns the Var123Number field value if set, zero value otherwise.
 func (o *Name) GetVar123Number() int32 {
-	if o == nil || isNil(o.Var123Number) {
+	if o == nil || IsNil(o.Var123Number) {
 		var ret int32
 		return ret
 	}
@@ -143,7 +143,7 @@ func (o *Name) GetVar123Number() int32 {
 // GetVar123NumberOk returns a tuple with the Var123Number field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Name) GetVar123NumberOk() (*int32, bool) {
-	if o == nil || isNil(o.Var123Number) {
+	if o == nil || IsNil(o.Var123Number) {
 		return nil, false
 	}
 	return o.Var123Number, true
@@ -151,7 +151,7 @@ func (o *Name) GetVar123NumberOk() (*int32, bool) {
 
 // HasVar123Number returns a boolean if a field has been set.
 func (o *Name) HasVar123Number() bool {
-	if o != nil && !isNil(o.Var123Number) {
+	if o != nil && !IsNil(o.Var123Number) {
 		return true
 	}
 
@@ -175,7 +175,7 @@ func (o Name) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
 	toSerialize["name"] = o.Name
 	// skip: snake_case is readOnly
-	if !isNil(o.Property) {
+	if !IsNil(o.Property) {
 		toSerialize["property"] = o.Property
 	}
 	// skip: 123Number is readOnly
diff --git a/samples/client/petstore/go/go-petstore/model_number_only.go b/samples/client/petstore/go/go-petstore/model_number_only.go
index 59680e79eed..629549ba988 100644
--- a/samples/client/petstore/go/go-petstore/model_number_only.go
+++ b/samples/client/petstore/go/go-petstore/model_number_only.go
@@ -41,7 +41,7 @@ func NewNumberOnlyWithDefaults() *NumberOnly {
 
 // GetJustNumber returns the JustNumber field value if set, zero value otherwise.
 func (o *NumberOnly) GetJustNumber() float32 {
-	if o == nil || isNil(o.JustNumber) {
+	if o == nil || IsNil(o.JustNumber) {
 		var ret float32
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *NumberOnly) GetJustNumber() float32 {
 // GetJustNumberOk returns a tuple with the JustNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *NumberOnly) GetJustNumberOk() (*float32, bool) {
-	if o == nil || isNil(o.JustNumber) {
+	if o == nil || IsNil(o.JustNumber) {
 		return nil, false
 	}
 	return o.JustNumber, true
@@ -59,7 +59,7 @@ func (o *NumberOnly) GetJustNumberOk() (*float32, bool) {
 
 // HasJustNumber returns a boolean if a field has been set.
 func (o *NumberOnly) HasJustNumber() bool {
-	if o != nil && !isNil(o.JustNumber) {
+	if o != nil && !IsNil(o.JustNumber) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o NumberOnly) MarshalJSON() ([]byte, error) {
 
 func (o NumberOnly) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.JustNumber) {
+	if !IsNil(o.JustNumber) {
 		toSerialize["JustNumber"] = o.JustNumber
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_order.go b/samples/client/petstore/go/go-petstore/model_order.go
index ad716c52f77..d403c611333 100644
--- a/samples/client/petstore/go/go-petstore/model_order.go
+++ b/samples/client/petstore/go/go-petstore/model_order.go
@@ -52,7 +52,7 @@ func NewOrderWithDefaults() *Order {
 
 // GetId returns the Id field value if set, zero value otherwise.
 func (o *Order) GetId() int64 {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		var ret int64
 		return ret
 	}
@@ -62,7 +62,7 @@ func (o *Order) GetId() int64 {
 // GetIdOk returns a tuple with the Id field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		return nil, false
 	}
 	return o.Id, true
@@ -70,7 +70,7 @@ func (o *Order) GetIdOk() (*int64, bool) {
 
 // HasId returns a boolean if a field has been set.
 func (o *Order) HasId() bool {
-	if o != nil && !isNil(o.Id) {
+	if o != nil && !IsNil(o.Id) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o *Order) SetId(v int64) {
 
 // GetPetId returns the PetId field value if set, zero value otherwise.
 func (o *Order) GetPetId() int64 {
-	if o == nil || isNil(o.PetId) {
+	if o == nil || IsNil(o.PetId) {
 		var ret int64
 		return ret
 	}
@@ -94,7 +94,7 @@ func (o *Order) GetPetId() int64 {
 // GetPetIdOk returns a tuple with the PetId field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetPetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.PetId) {
+	if o == nil || IsNil(o.PetId) {
 		return nil, false
 	}
 	return o.PetId, true
@@ -102,7 +102,7 @@ func (o *Order) GetPetIdOk() (*int64, bool) {
 
 // HasPetId returns a boolean if a field has been set.
 func (o *Order) HasPetId() bool {
-	if o != nil && !isNil(o.PetId) {
+	if o != nil && !IsNil(o.PetId) {
 		return true
 	}
 
@@ -116,7 +116,7 @@ func (o *Order) SetPetId(v int64) {
 
 // GetQuantity returns the Quantity field value if set, zero value otherwise.
 func (o *Order) GetQuantity() int32 {
-	if o == nil || isNil(o.Quantity) {
+	if o == nil || IsNil(o.Quantity) {
 		var ret int32
 		return ret
 	}
@@ -126,7 +126,7 @@ func (o *Order) GetQuantity() int32 {
 // GetQuantityOk returns a tuple with the Quantity field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetQuantityOk() (*int32, bool) {
-	if o == nil || isNil(o.Quantity) {
+	if o == nil || IsNil(o.Quantity) {
 		return nil, false
 	}
 	return o.Quantity, true
@@ -134,7 +134,7 @@ func (o *Order) GetQuantityOk() (*int32, bool) {
 
 // HasQuantity returns a boolean if a field has been set.
 func (o *Order) HasQuantity() bool {
-	if o != nil && !isNil(o.Quantity) {
+	if o != nil && !IsNil(o.Quantity) {
 		return true
 	}
 
@@ -148,7 +148,7 @@ func (o *Order) SetQuantity(v int32) {
 
 // GetShipDate returns the ShipDate field value if set, zero value otherwise.
 func (o *Order) GetShipDate() time.Time {
-	if o == nil || isNil(o.ShipDate) {
+	if o == nil || IsNil(o.ShipDate) {
 		var ret time.Time
 		return ret
 	}
@@ -158,7 +158,7 @@ func (o *Order) GetShipDate() time.Time {
 // GetShipDateOk returns a tuple with the ShipDate field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetShipDateOk() (*time.Time, bool) {
-	if o == nil || isNil(o.ShipDate) {
+	if o == nil || IsNil(o.ShipDate) {
 		return nil, false
 	}
 	return o.ShipDate, true
@@ -166,7 +166,7 @@ func (o *Order) GetShipDateOk() (*time.Time, bool) {
 
 // HasShipDate returns a boolean if a field has been set.
 func (o *Order) HasShipDate() bool {
-	if o != nil && !isNil(o.ShipDate) {
+	if o != nil && !IsNil(o.ShipDate) {
 		return true
 	}
 
@@ -180,7 +180,7 @@ func (o *Order) SetShipDate(v time.Time) {
 
 // GetStatus returns the Status field value if set, zero value otherwise.
 func (o *Order) GetStatus() string {
-	if o == nil || isNil(o.Status) {
+	if o == nil || IsNil(o.Status) {
 		var ret string
 		return ret
 	}
@@ -190,7 +190,7 @@ func (o *Order) GetStatus() string {
 // GetStatusOk returns a tuple with the Status field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetStatusOk() (*string, bool) {
-	if o == nil || isNil(o.Status) {
+	if o == nil || IsNil(o.Status) {
 		return nil, false
 	}
 	return o.Status, true
@@ -198,7 +198,7 @@ func (o *Order) GetStatusOk() (*string, bool) {
 
 // HasStatus returns a boolean if a field has been set.
 func (o *Order) HasStatus() bool {
-	if o != nil && !isNil(o.Status) {
+	if o != nil && !IsNil(o.Status) {
 		return true
 	}
 
@@ -212,7 +212,7 @@ func (o *Order) SetStatus(v string) {
 
 // GetComplete returns the Complete field value if set, zero value otherwise.
 func (o *Order) GetComplete() bool {
-	if o == nil || isNil(o.Complete) {
+	if o == nil || IsNil(o.Complete) {
 		var ret bool
 		return ret
 	}
@@ -222,7 +222,7 @@ func (o *Order) GetComplete() bool {
 // GetCompleteOk returns a tuple with the Complete field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetCompleteOk() (*bool, bool) {
-	if o == nil || isNil(o.Complete) {
+	if o == nil || IsNil(o.Complete) {
 		return nil, false
 	}
 	return o.Complete, true
@@ -230,7 +230,7 @@ func (o *Order) GetCompleteOk() (*bool, bool) {
 
 // HasComplete returns a boolean if a field has been set.
 func (o *Order) HasComplete() bool {
-	if o != nil && !isNil(o.Complete) {
+	if o != nil && !IsNil(o.Complete) {
 		return true
 	}
 
@@ -252,22 +252,22 @@ func (o Order) MarshalJSON() ([]byte, error) {
 
 func (o Order) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Id) {
+	if !IsNil(o.Id) {
 		toSerialize["id"] = o.Id
 	}
-	if !isNil(o.PetId) {
+	if !IsNil(o.PetId) {
 		toSerialize["petId"] = o.PetId
 	}
-	if !isNil(o.Quantity) {
+	if !IsNil(o.Quantity) {
 		toSerialize["quantity"] = o.Quantity
 	}
-	if !isNil(o.ShipDate) {
+	if !IsNil(o.ShipDate) {
 		toSerialize["shipDate"] = o.ShipDate
 	}
-	if !isNil(o.Status) {
+	if !IsNil(o.Status) {
 		toSerialize["status"] = o.Status
 	}
-	if !isNil(o.Complete) {
+	if !IsNil(o.Complete) {
 		toSerialize["complete"] = o.Complete
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_outer_composite.go b/samples/client/petstore/go/go-petstore/model_outer_composite.go
index df79c41cc92..4758b3a952f 100644
--- a/samples/client/petstore/go/go-petstore/model_outer_composite.go
+++ b/samples/client/petstore/go/go-petstore/model_outer_composite.go
@@ -43,7 +43,7 @@ func NewOuterCompositeWithDefaults() *OuterComposite {
 
 // GetMyNumber returns the MyNumber field value if set, zero value otherwise.
 func (o *OuterComposite) GetMyNumber() float32 {
-	if o == nil || isNil(o.MyNumber) {
+	if o == nil || IsNil(o.MyNumber) {
 		var ret float32
 		return ret
 	}
@@ -53,7 +53,7 @@ func (o *OuterComposite) GetMyNumber() float32 {
 // GetMyNumberOk returns a tuple with the MyNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *OuterComposite) GetMyNumberOk() (*float32, bool) {
-	if o == nil || isNil(o.MyNumber) {
+	if o == nil || IsNil(o.MyNumber) {
 		return nil, false
 	}
 	return o.MyNumber, true
@@ -61,7 +61,7 @@ func (o *OuterComposite) GetMyNumberOk() (*float32, bool) {
 
 // HasMyNumber returns a boolean if a field has been set.
 func (o *OuterComposite) HasMyNumber() bool {
-	if o != nil && !isNil(o.MyNumber) {
+	if o != nil && !IsNil(o.MyNumber) {
 		return true
 	}
 
@@ -75,7 +75,7 @@ func (o *OuterComposite) SetMyNumber(v float32) {
 
 // GetMyString returns the MyString field value if set, zero value otherwise.
 func (o *OuterComposite) GetMyString() string {
-	if o == nil || isNil(o.MyString) {
+	if o == nil || IsNil(o.MyString) {
 		var ret string
 		return ret
 	}
@@ -85,7 +85,7 @@ func (o *OuterComposite) GetMyString() string {
 // GetMyStringOk returns a tuple with the MyString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *OuterComposite) GetMyStringOk() (*string, bool) {
-	if o == nil || isNil(o.MyString) {
+	if o == nil || IsNil(o.MyString) {
 		return nil, false
 	}
 	return o.MyString, true
@@ -93,7 +93,7 @@ func (o *OuterComposite) GetMyStringOk() (*string, bool) {
 
 // HasMyString returns a boolean if a field has been set.
 func (o *OuterComposite) HasMyString() bool {
-	if o != nil && !isNil(o.MyString) {
+	if o != nil && !IsNil(o.MyString) {
 		return true
 	}
 
@@ -107,7 +107,7 @@ func (o *OuterComposite) SetMyString(v string) {
 
 // GetMyBoolean returns the MyBoolean field value if set, zero value otherwise.
 func (o *OuterComposite) GetMyBoolean() bool {
-	if o == nil || isNil(o.MyBoolean) {
+	if o == nil || IsNil(o.MyBoolean) {
 		var ret bool
 		return ret
 	}
@@ -117,7 +117,7 @@ func (o *OuterComposite) GetMyBoolean() bool {
 // GetMyBooleanOk returns a tuple with the MyBoolean field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *OuterComposite) GetMyBooleanOk() (*bool, bool) {
-	if o == nil || isNil(o.MyBoolean) {
+	if o == nil || IsNil(o.MyBoolean) {
 		return nil, false
 	}
 	return o.MyBoolean, true
@@ -125,7 +125,7 @@ func (o *OuterComposite) GetMyBooleanOk() (*bool, bool) {
 
 // HasMyBoolean returns a boolean if a field has been set.
 func (o *OuterComposite) HasMyBoolean() bool {
-	if o != nil && !isNil(o.MyBoolean) {
+	if o != nil && !IsNil(o.MyBoolean) {
 		return true
 	}
 
@@ -147,13 +147,13 @@ func (o OuterComposite) MarshalJSON() ([]byte, error) {
 
 func (o OuterComposite) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.MyNumber) {
+	if !IsNil(o.MyNumber) {
 		toSerialize["my_number"] = o.MyNumber
 	}
-	if !isNil(o.MyString) {
+	if !IsNil(o.MyString) {
 		toSerialize["my_string"] = o.MyString
 	}
-	if !isNil(o.MyBoolean) {
+	if !IsNil(o.MyBoolean) {
 		toSerialize["my_boolean"] = o.MyBoolean
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_pet.go b/samples/client/petstore/go/go-petstore/model_pet.go
index 9fc22cdd45a..04ae05c1e18 100644
--- a/samples/client/petstore/go/go-petstore/model_pet.go
+++ b/samples/client/petstore/go/go-petstore/model_pet.go
@@ -49,7 +49,7 @@ func NewPetWithDefaults() *Pet {
 
 // GetId returns the Id field value if set, zero value otherwise.
 func (o *Pet) GetId() int64 {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		var ret int64
 		return ret
 	}
@@ -59,7 +59,7 @@ func (o *Pet) GetId() int64 {
 // GetIdOk returns a tuple with the Id field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Pet) GetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		return nil, false
 	}
 	return o.Id, true
@@ -67,7 +67,7 @@ func (o *Pet) GetIdOk() (*int64, bool) {
 
 // HasId returns a boolean if a field has been set.
 func (o *Pet) HasId() bool {
-	if o != nil && !isNil(o.Id) {
+	if o != nil && !IsNil(o.Id) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o *Pet) SetId(v int64) {
 
 // GetCategory returns the Category field value if set, zero value otherwise.
 func (o *Pet) GetCategory() Category {
-	if o == nil || isNil(o.Category) {
+	if o == nil || IsNil(o.Category) {
 		var ret Category
 		return ret
 	}
@@ -91,7 +91,7 @@ func (o *Pet) GetCategory() Category {
 // GetCategoryOk returns a tuple with the Category field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Pet) GetCategoryOk() (*Category, bool) {
-	if o == nil || isNil(o.Category) {
+	if o == nil || IsNil(o.Category) {
 		return nil, false
 	}
 	return o.Category, true
@@ -99,7 +99,7 @@ func (o *Pet) GetCategoryOk() (*Category, bool) {
 
 // HasCategory returns a boolean if a field has been set.
 func (o *Pet) HasCategory() bool {
-	if o != nil && !isNil(o.Category) {
+	if o != nil && !IsNil(o.Category) {
 		return true
 	}
 
@@ -161,7 +161,7 @@ func (o *Pet) SetPhotoUrls(v []string) {
 
 // GetTags returns the Tags field value if set, zero value otherwise.
 func (o *Pet) GetTags() []Tag {
-	if o == nil || isNil(o.Tags) {
+	if o == nil || IsNil(o.Tags) {
 		var ret []Tag
 		return ret
 	}
@@ -171,7 +171,7 @@ func (o *Pet) GetTags() []Tag {
 // GetTagsOk returns a tuple with the Tags field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Pet) GetTagsOk() ([]Tag, bool) {
-	if o == nil || isNil(o.Tags) {
+	if o == nil || IsNil(o.Tags) {
 		return nil, false
 	}
 	return o.Tags, true
@@ -179,7 +179,7 @@ func (o *Pet) GetTagsOk() ([]Tag, bool) {
 
 // HasTags returns a boolean if a field has been set.
 func (o *Pet) HasTags() bool {
-	if o != nil && !isNil(o.Tags) {
+	if o != nil && !IsNil(o.Tags) {
 		return true
 	}
 
@@ -193,7 +193,7 @@ func (o *Pet) SetTags(v []Tag) {
 
 // GetStatus returns the Status field value if set, zero value otherwise.
 func (o *Pet) GetStatus() string {
-	if o == nil || isNil(o.Status) {
+	if o == nil || IsNil(o.Status) {
 		var ret string
 		return ret
 	}
@@ -203,7 +203,7 @@ func (o *Pet) GetStatus() string {
 // GetStatusOk returns a tuple with the Status field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Pet) GetStatusOk() (*string, bool) {
-	if o == nil || isNil(o.Status) {
+	if o == nil || IsNil(o.Status) {
 		return nil, false
 	}
 	return o.Status, true
@@ -211,7 +211,7 @@ func (o *Pet) GetStatusOk() (*string, bool) {
 
 // HasStatus returns a boolean if a field has been set.
 func (o *Pet) HasStatus() bool {
-	if o != nil && !isNil(o.Status) {
+	if o != nil && !IsNil(o.Status) {
 		return true
 	}
 
@@ -233,18 +233,18 @@ func (o Pet) MarshalJSON() ([]byte, error) {
 
 func (o Pet) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Id) {
+	if !IsNil(o.Id) {
 		toSerialize["id"] = o.Id
 	}
-	if !isNil(o.Category) {
+	if !IsNil(o.Category) {
 		toSerialize["category"] = o.Category
 	}
 	toSerialize["name"] = o.Name
 	toSerialize["photoUrls"] = o.PhotoUrls
-	if !isNil(o.Tags) {
+	if !IsNil(o.Tags) {
 		toSerialize["tags"] = o.Tags
 	}
-	if !isNil(o.Status) {
+	if !IsNil(o.Status) {
 		toSerialize["status"] = o.Status
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_read_only_first.go b/samples/client/petstore/go/go-petstore/model_read_only_first.go
index 95ab3c11cb2..c5951776226 100644
--- a/samples/client/petstore/go/go-petstore/model_read_only_first.go
+++ b/samples/client/petstore/go/go-petstore/model_read_only_first.go
@@ -42,7 +42,7 @@ func NewReadOnlyFirstWithDefaults() *ReadOnlyFirst {
 
 // GetBar returns the Bar field value if set, zero value otherwise.
 func (o *ReadOnlyFirst) GetBar() string {
-	if o == nil || isNil(o.Bar) {
+	if o == nil || IsNil(o.Bar) {
 		var ret string
 		return ret
 	}
@@ -52,7 +52,7 @@ func (o *ReadOnlyFirst) GetBar() string {
 // GetBarOk returns a tuple with the Bar field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyFirst) GetBarOk() (*string, bool) {
-	if o == nil || isNil(o.Bar) {
+	if o == nil || IsNil(o.Bar) {
 		return nil, false
 	}
 	return o.Bar, true
@@ -60,7 +60,7 @@ func (o *ReadOnlyFirst) GetBarOk() (*string, bool) {
 
 // HasBar returns a boolean if a field has been set.
 func (o *ReadOnlyFirst) HasBar() bool {
-	if o != nil && !isNil(o.Bar) {
+	if o != nil && !IsNil(o.Bar) {
 		return true
 	}
 
@@ -74,7 +74,7 @@ func (o *ReadOnlyFirst) SetBar(v string) {
 
 // GetBaz returns the Baz field value if set, zero value otherwise.
 func (o *ReadOnlyFirst) GetBaz() string {
-	if o == nil || isNil(o.Baz) {
+	if o == nil || IsNil(o.Baz) {
 		var ret string
 		return ret
 	}
@@ -84,7 +84,7 @@ func (o *ReadOnlyFirst) GetBaz() string {
 // GetBazOk returns a tuple with the Baz field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyFirst) GetBazOk() (*string, bool) {
-	if o == nil || isNil(o.Baz) {
+	if o == nil || IsNil(o.Baz) {
 		return nil, false
 	}
 	return o.Baz, true
@@ -92,7 +92,7 @@ func (o *ReadOnlyFirst) GetBazOk() (*string, bool) {
 
 // HasBaz returns a boolean if a field has been set.
 func (o *ReadOnlyFirst) HasBaz() bool {
-	if o != nil && !isNil(o.Baz) {
+	if o != nil && !IsNil(o.Baz) {
 		return true
 	}
 
@@ -115,7 +115,7 @@ func (o ReadOnlyFirst) MarshalJSON() ([]byte, error) {
 func (o ReadOnlyFirst) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
 	// skip: bar is readOnly
-	if !isNil(o.Baz) {
+	if !IsNil(o.Baz) {
 		toSerialize["baz"] = o.Baz
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_return.go b/samples/client/petstore/go/go-petstore/model_return.go
index 42ee8639436..bc2bdb01444 100644
--- a/samples/client/petstore/go/go-petstore/model_return.go
+++ b/samples/client/petstore/go/go-petstore/model_return.go
@@ -41,7 +41,7 @@ func NewReturnWithDefaults() *Return {
 
 // GetReturn returns the Return field value if set, zero value otherwise.
 func (o *Return) GetReturn() int32 {
-	if o == nil || isNil(o.Return) {
+	if o == nil || IsNil(o.Return) {
 		var ret int32
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *Return) GetReturn() int32 {
 // GetReturnOk returns a tuple with the Return field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Return) GetReturnOk() (*int32, bool) {
-	if o == nil || isNil(o.Return) {
+	if o == nil || IsNil(o.Return) {
 		return nil, false
 	}
 	return o.Return, true
@@ -59,7 +59,7 @@ func (o *Return) GetReturnOk() (*int32, bool) {
 
 // HasReturn returns a boolean if a field has been set.
 func (o *Return) HasReturn() bool {
-	if o != nil && !isNil(o.Return) {
+	if o != nil && !IsNil(o.Return) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o Return) MarshalJSON() ([]byte, error) {
 
 func (o Return) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Return) {
+	if !IsNil(o.Return) {
 		toSerialize["return"] = o.Return
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_special_model_name.go b/samples/client/petstore/go/go-petstore/model_special_model_name.go
index 3f2c3504e2b..3811893dcad 100644
--- a/samples/client/petstore/go/go-petstore/model_special_model_name.go
+++ b/samples/client/petstore/go/go-petstore/model_special_model_name.go
@@ -41,7 +41,7 @@ func NewSpecialModelNameWithDefaults() *SpecialModelName {
 
 // GetSpecialPropertyName returns the SpecialPropertyName field value if set, zero value otherwise.
 func (o *SpecialModelName) GetSpecialPropertyName() int64 {
-	if o == nil || isNil(o.SpecialPropertyName) {
+	if o == nil || IsNil(o.SpecialPropertyName) {
 		var ret int64
 		return ret
 	}
@@ -51,7 +51,7 @@ func (o *SpecialModelName) GetSpecialPropertyName() int64 {
 // GetSpecialPropertyNameOk returns a tuple with the SpecialPropertyName field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *SpecialModelName) GetSpecialPropertyNameOk() (*int64, bool) {
-	if o == nil || isNil(o.SpecialPropertyName) {
+	if o == nil || IsNil(o.SpecialPropertyName) {
 		return nil, false
 	}
 	return o.SpecialPropertyName, true
@@ -59,7 +59,7 @@ func (o *SpecialModelName) GetSpecialPropertyNameOk() (*int64, bool) {
 
 // HasSpecialPropertyName returns a boolean if a field has been set.
 func (o *SpecialModelName) HasSpecialPropertyName() bool {
-	if o != nil && !isNil(o.SpecialPropertyName) {
+	if o != nil && !IsNil(o.SpecialPropertyName) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o SpecialModelName) MarshalJSON() ([]byte, error) {
 
 func (o SpecialModelName) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.SpecialPropertyName) {
+	if !IsNil(o.SpecialPropertyName) {
 		toSerialize["$special[property.name]"] = o.SpecialPropertyName
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_tag.go b/samples/client/petstore/go/go-petstore/model_tag.go
index 9842add4494..fe001247a88 100644
--- a/samples/client/petstore/go/go-petstore/model_tag.go
+++ b/samples/client/petstore/go/go-petstore/model_tag.go
@@ -42,7 +42,7 @@ func NewTagWithDefaults() *Tag {
 
 // GetId returns the Id field value if set, zero value otherwise.
 func (o *Tag) GetId() int64 {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		var ret int64
 		return ret
 	}
@@ -52,7 +52,7 @@ func (o *Tag) GetId() int64 {
 // GetIdOk returns a tuple with the Id field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Tag) GetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		return nil, false
 	}
 	return o.Id, true
@@ -60,7 +60,7 @@ func (o *Tag) GetIdOk() (*int64, bool) {
 
 // HasId returns a boolean if a field has been set.
 func (o *Tag) HasId() bool {
-	if o != nil && !isNil(o.Id) {
+	if o != nil && !IsNil(o.Id) {
 		return true
 	}
 
@@ -74,7 +74,7 @@ func (o *Tag) SetId(v int64) {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *Tag) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -84,7 +84,7 @@ func (o *Tag) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Tag) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -92,7 +92,7 @@ func (o *Tag) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *Tag) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -114,10 +114,10 @@ func (o Tag) MarshalJSON() ([]byte, error) {
 
 func (o Tag) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Id) {
+	if !IsNil(o.Id) {
 		toSerialize["id"] = o.Id
 	}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_user.go b/samples/client/petstore/go/go-petstore/model_user.go
index f4fa27a5015..f1ccca8efdc 100644
--- a/samples/client/petstore/go/go-petstore/model_user.go
+++ b/samples/client/petstore/go/go-petstore/model_user.go
@@ -49,7 +49,7 @@ func NewUserWithDefaults() *User {
 
 // GetId returns the Id field value if set, zero value otherwise.
 func (o *User) GetId() int64 {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		var ret int64
 		return ret
 	}
@@ -59,7 +59,7 @@ func (o *User) GetId() int64 {
 // GetIdOk returns a tuple with the Id field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		return nil, false
 	}
 	return o.Id, true
@@ -67,7 +67,7 @@ func (o *User) GetIdOk() (*int64, bool) {
 
 // HasId returns a boolean if a field has been set.
 func (o *User) HasId() bool {
-	if o != nil && !isNil(o.Id) {
+	if o != nil && !IsNil(o.Id) {
 		return true
 	}
 
@@ -81,7 +81,7 @@ func (o *User) SetId(v int64) {
 
 // GetUsername returns the Username field value if set, zero value otherwise.
 func (o *User) GetUsername() string {
-	if o == nil || isNil(o.Username) {
+	if o == nil || IsNil(o.Username) {
 		var ret string
 		return ret
 	}
@@ -91,7 +91,7 @@ func (o *User) GetUsername() string {
 // GetUsernameOk returns a tuple with the Username field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetUsernameOk() (*string, bool) {
-	if o == nil || isNil(o.Username) {
+	if o == nil || IsNil(o.Username) {
 		return nil, false
 	}
 	return o.Username, true
@@ -99,7 +99,7 @@ func (o *User) GetUsernameOk() (*string, bool) {
 
 // HasUsername returns a boolean if a field has been set.
 func (o *User) HasUsername() bool {
-	if o != nil && !isNil(o.Username) {
+	if o != nil && !IsNil(o.Username) {
 		return true
 	}
 
@@ -113,7 +113,7 @@ func (o *User) SetUsername(v string) {
 
 // GetFirstName returns the FirstName field value if set, zero value otherwise.
 func (o *User) GetFirstName() string {
-	if o == nil || isNil(o.FirstName) {
+	if o == nil || IsNil(o.FirstName) {
 		var ret string
 		return ret
 	}
@@ -123,7 +123,7 @@ func (o *User) GetFirstName() string {
 // GetFirstNameOk returns a tuple with the FirstName field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetFirstNameOk() (*string, bool) {
-	if o == nil || isNil(o.FirstName) {
+	if o == nil || IsNil(o.FirstName) {
 		return nil, false
 	}
 	return o.FirstName, true
@@ -131,7 +131,7 @@ func (o *User) GetFirstNameOk() (*string, bool) {
 
 // HasFirstName returns a boolean if a field has been set.
 func (o *User) HasFirstName() bool {
-	if o != nil && !isNil(o.FirstName) {
+	if o != nil && !IsNil(o.FirstName) {
 		return true
 	}
 
@@ -145,7 +145,7 @@ func (o *User) SetFirstName(v string) {
 
 // GetLastName returns the LastName field value if set, zero value otherwise.
 func (o *User) GetLastName() string {
-	if o == nil || isNil(o.LastName) {
+	if o == nil || IsNil(o.LastName) {
 		var ret string
 		return ret
 	}
@@ -155,7 +155,7 @@ func (o *User) GetLastName() string {
 // GetLastNameOk returns a tuple with the LastName field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetLastNameOk() (*string, bool) {
-	if o == nil || isNil(o.LastName) {
+	if o == nil || IsNil(o.LastName) {
 		return nil, false
 	}
 	return o.LastName, true
@@ -163,7 +163,7 @@ func (o *User) GetLastNameOk() (*string, bool) {
 
 // HasLastName returns a boolean if a field has been set.
 func (o *User) HasLastName() bool {
-	if o != nil && !isNil(o.LastName) {
+	if o != nil && !IsNil(o.LastName) {
 		return true
 	}
 
@@ -177,7 +177,7 @@ func (o *User) SetLastName(v string) {
 
 // GetEmail returns the Email field value if set, zero value otherwise.
 func (o *User) GetEmail() string {
-	if o == nil || isNil(o.Email) {
+	if o == nil || IsNil(o.Email) {
 		var ret string
 		return ret
 	}
@@ -187,7 +187,7 @@ func (o *User) GetEmail() string {
 // GetEmailOk returns a tuple with the Email field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetEmailOk() (*string, bool) {
-	if o == nil || isNil(o.Email) {
+	if o == nil || IsNil(o.Email) {
 		return nil, false
 	}
 	return o.Email, true
@@ -195,7 +195,7 @@ func (o *User) GetEmailOk() (*string, bool) {
 
 // HasEmail returns a boolean if a field has been set.
 func (o *User) HasEmail() bool {
-	if o != nil && !isNil(o.Email) {
+	if o != nil && !IsNil(o.Email) {
 		return true
 	}
 
@@ -209,7 +209,7 @@ func (o *User) SetEmail(v string) {
 
 // GetPassword returns the Password field value if set, zero value otherwise.
 func (o *User) GetPassword() string {
-	if o == nil || isNil(o.Password) {
+	if o == nil || IsNil(o.Password) {
 		var ret string
 		return ret
 	}
@@ -219,7 +219,7 @@ func (o *User) GetPassword() string {
 // GetPasswordOk returns a tuple with the Password field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetPasswordOk() (*string, bool) {
-	if o == nil || isNil(o.Password) {
+	if o == nil || IsNil(o.Password) {
 		return nil, false
 	}
 	return o.Password, true
@@ -227,7 +227,7 @@ func (o *User) GetPasswordOk() (*string, bool) {
 
 // HasPassword returns a boolean if a field has been set.
 func (o *User) HasPassword() bool {
-	if o != nil && !isNil(o.Password) {
+	if o != nil && !IsNil(o.Password) {
 		return true
 	}
 
@@ -241,7 +241,7 @@ func (o *User) SetPassword(v string) {
 
 // GetPhone returns the Phone field value if set, zero value otherwise.
 func (o *User) GetPhone() string {
-	if o == nil || isNil(o.Phone) {
+	if o == nil || IsNil(o.Phone) {
 		var ret string
 		return ret
 	}
@@ -251,7 +251,7 @@ func (o *User) GetPhone() string {
 // GetPhoneOk returns a tuple with the Phone field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetPhoneOk() (*string, bool) {
-	if o == nil || isNil(o.Phone) {
+	if o == nil || IsNil(o.Phone) {
 		return nil, false
 	}
 	return o.Phone, true
@@ -259,7 +259,7 @@ func (o *User) GetPhoneOk() (*string, bool) {
 
 // HasPhone returns a boolean if a field has been set.
 func (o *User) HasPhone() bool {
-	if o != nil && !isNil(o.Phone) {
+	if o != nil && !IsNil(o.Phone) {
 		return true
 	}
 
@@ -273,7 +273,7 @@ func (o *User) SetPhone(v string) {
 
 // GetUserStatus returns the UserStatus field value if set, zero value otherwise.
 func (o *User) GetUserStatus() int32 {
-	if o == nil || isNil(o.UserStatus) {
+	if o == nil || IsNil(o.UserStatus) {
 		var ret int32
 		return ret
 	}
@@ -283,7 +283,7 @@ func (o *User) GetUserStatus() int32 {
 // GetUserStatusOk returns a tuple with the UserStatus field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetUserStatusOk() (*int32, bool) {
-	if o == nil || isNil(o.UserStatus) {
+	if o == nil || IsNil(o.UserStatus) {
 		return nil, false
 	}
 	return o.UserStatus, true
@@ -291,7 +291,7 @@ func (o *User) GetUserStatusOk() (*int32, bool) {
 
 // HasUserStatus returns a boolean if a field has been set.
 func (o *User) HasUserStatus() bool {
-	if o != nil && !isNil(o.UserStatus) {
+	if o != nil && !IsNil(o.UserStatus) {
 		return true
 	}
 
@@ -313,28 +313,28 @@ func (o User) MarshalJSON() ([]byte, error) {
 
 func (o User) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Id) {
+	if !IsNil(o.Id) {
 		toSerialize["id"] = o.Id
 	}
-	if !isNil(o.Username) {
+	if !IsNil(o.Username) {
 		toSerialize["username"] = o.Username
 	}
-	if !isNil(o.FirstName) {
+	if !IsNil(o.FirstName) {
 		toSerialize["firstName"] = o.FirstName
 	}
-	if !isNil(o.LastName) {
+	if !IsNil(o.LastName) {
 		toSerialize["lastName"] = o.LastName
 	}
-	if !isNil(o.Email) {
+	if !IsNil(o.Email) {
 		toSerialize["email"] = o.Email
 	}
-	if !isNil(o.Password) {
+	if !IsNil(o.Password) {
 		toSerialize["password"] = o.Password
 	}
-	if !isNil(o.Phone) {
+	if !IsNil(o.Phone) {
 		toSerialize["phone"] = o.Phone
 	}
-	if !isNil(o.UserStatus) {
+	if !IsNil(o.UserStatus) {
 		toSerialize["userStatus"] = o.UserStatus
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/model_xml_item.go b/samples/client/petstore/go/go-petstore/model_xml_item.go
index 994aa905d54..7632c89d71d 100644
--- a/samples/client/petstore/go/go-petstore/model_xml_item.go
+++ b/samples/client/petstore/go/go-petstore/model_xml_item.go
@@ -69,7 +69,7 @@ func NewXmlItemWithDefaults() *XmlItem {
 
 // GetAttributeString returns the AttributeString field value if set, zero value otherwise.
 func (o *XmlItem) GetAttributeString() string {
-	if o == nil || isNil(o.AttributeString) {
+	if o == nil || IsNil(o.AttributeString) {
 		var ret string
 		return ret
 	}
@@ -79,7 +79,7 @@ func (o *XmlItem) GetAttributeString() string {
 // GetAttributeStringOk returns a tuple with the AttributeString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetAttributeStringOk() (*string, bool) {
-	if o == nil || isNil(o.AttributeString) {
+	if o == nil || IsNil(o.AttributeString) {
 		return nil, false
 	}
 	return o.AttributeString, true
@@ -87,7 +87,7 @@ func (o *XmlItem) GetAttributeStringOk() (*string, bool) {
 
 // HasAttributeString returns a boolean if a field has been set.
 func (o *XmlItem) HasAttributeString() bool {
-	if o != nil && !isNil(o.AttributeString) {
+	if o != nil && !IsNil(o.AttributeString) {
 		return true
 	}
 
@@ -101,7 +101,7 @@ func (o *XmlItem) SetAttributeString(v string) {
 
 // GetAttributeNumber returns the AttributeNumber field value if set, zero value otherwise.
 func (o *XmlItem) GetAttributeNumber() float32 {
-	if o == nil || isNil(o.AttributeNumber) {
+	if o == nil || IsNil(o.AttributeNumber) {
 		var ret float32
 		return ret
 	}
@@ -111,7 +111,7 @@ func (o *XmlItem) GetAttributeNumber() float32 {
 // GetAttributeNumberOk returns a tuple with the AttributeNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetAttributeNumberOk() (*float32, bool) {
-	if o == nil || isNil(o.AttributeNumber) {
+	if o == nil || IsNil(o.AttributeNumber) {
 		return nil, false
 	}
 	return o.AttributeNumber, true
@@ -119,7 +119,7 @@ func (o *XmlItem) GetAttributeNumberOk() (*float32, bool) {
 
 // HasAttributeNumber returns a boolean if a field has been set.
 func (o *XmlItem) HasAttributeNumber() bool {
-	if o != nil && !isNil(o.AttributeNumber) {
+	if o != nil && !IsNil(o.AttributeNumber) {
 		return true
 	}
 
@@ -133,7 +133,7 @@ func (o *XmlItem) SetAttributeNumber(v float32) {
 
 // GetAttributeInteger returns the AttributeInteger field value if set, zero value otherwise.
 func (o *XmlItem) GetAttributeInteger() int32 {
-	if o == nil || isNil(o.AttributeInteger) {
+	if o == nil || IsNil(o.AttributeInteger) {
 		var ret int32
 		return ret
 	}
@@ -143,7 +143,7 @@ func (o *XmlItem) GetAttributeInteger() int32 {
 // GetAttributeIntegerOk returns a tuple with the AttributeInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetAttributeIntegerOk() (*int32, bool) {
-	if o == nil || isNil(o.AttributeInteger) {
+	if o == nil || IsNil(o.AttributeInteger) {
 		return nil, false
 	}
 	return o.AttributeInteger, true
@@ -151,7 +151,7 @@ func (o *XmlItem) GetAttributeIntegerOk() (*int32, bool) {
 
 // HasAttributeInteger returns a boolean if a field has been set.
 func (o *XmlItem) HasAttributeInteger() bool {
-	if o != nil && !isNil(o.AttributeInteger) {
+	if o != nil && !IsNil(o.AttributeInteger) {
 		return true
 	}
 
@@ -165,7 +165,7 @@ func (o *XmlItem) SetAttributeInteger(v int32) {
 
 // GetAttributeBoolean returns the AttributeBoolean field value if set, zero value otherwise.
 func (o *XmlItem) GetAttributeBoolean() bool {
-	if o == nil || isNil(o.AttributeBoolean) {
+	if o == nil || IsNil(o.AttributeBoolean) {
 		var ret bool
 		return ret
 	}
@@ -175,7 +175,7 @@ func (o *XmlItem) GetAttributeBoolean() bool {
 // GetAttributeBooleanOk returns a tuple with the AttributeBoolean field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetAttributeBooleanOk() (*bool, bool) {
-	if o == nil || isNil(o.AttributeBoolean) {
+	if o == nil || IsNil(o.AttributeBoolean) {
 		return nil, false
 	}
 	return o.AttributeBoolean, true
@@ -183,7 +183,7 @@ func (o *XmlItem) GetAttributeBooleanOk() (*bool, bool) {
 
 // HasAttributeBoolean returns a boolean if a field has been set.
 func (o *XmlItem) HasAttributeBoolean() bool {
-	if o != nil && !isNil(o.AttributeBoolean) {
+	if o != nil && !IsNil(o.AttributeBoolean) {
 		return true
 	}
 
@@ -197,7 +197,7 @@ func (o *XmlItem) SetAttributeBoolean(v bool) {
 
 // GetWrappedArray returns the WrappedArray field value if set, zero value otherwise.
 func (o *XmlItem) GetWrappedArray() []int32 {
-	if o == nil || isNil(o.WrappedArray) {
+	if o == nil || IsNil(o.WrappedArray) {
 		var ret []int32
 		return ret
 	}
@@ -207,7 +207,7 @@ func (o *XmlItem) GetWrappedArray() []int32 {
 // GetWrappedArrayOk returns a tuple with the WrappedArray field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetWrappedArrayOk() ([]int32, bool) {
-	if o == nil || isNil(o.WrappedArray) {
+	if o == nil || IsNil(o.WrappedArray) {
 		return nil, false
 	}
 	return o.WrappedArray, true
@@ -215,7 +215,7 @@ func (o *XmlItem) GetWrappedArrayOk() ([]int32, bool) {
 
 // HasWrappedArray returns a boolean if a field has been set.
 func (o *XmlItem) HasWrappedArray() bool {
-	if o != nil && !isNil(o.WrappedArray) {
+	if o != nil && !IsNil(o.WrappedArray) {
 		return true
 	}
 
@@ -229,7 +229,7 @@ func (o *XmlItem) SetWrappedArray(v []int32) {
 
 // GetNameString returns the NameString field value if set, zero value otherwise.
 func (o *XmlItem) GetNameString() string {
-	if o == nil || isNil(o.NameString) {
+	if o == nil || IsNil(o.NameString) {
 		var ret string
 		return ret
 	}
@@ -239,7 +239,7 @@ func (o *XmlItem) GetNameString() string {
 // GetNameStringOk returns a tuple with the NameString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNameStringOk() (*string, bool) {
-	if o == nil || isNil(o.NameString) {
+	if o == nil || IsNil(o.NameString) {
 		return nil, false
 	}
 	return o.NameString, true
@@ -247,7 +247,7 @@ func (o *XmlItem) GetNameStringOk() (*string, bool) {
 
 // HasNameString returns a boolean if a field has been set.
 func (o *XmlItem) HasNameString() bool {
-	if o != nil && !isNil(o.NameString) {
+	if o != nil && !IsNil(o.NameString) {
 		return true
 	}
 
@@ -261,7 +261,7 @@ func (o *XmlItem) SetNameString(v string) {
 
 // GetNameNumber returns the NameNumber field value if set, zero value otherwise.
 func (o *XmlItem) GetNameNumber() float32 {
-	if o == nil || isNil(o.NameNumber) {
+	if o == nil || IsNil(o.NameNumber) {
 		var ret float32
 		return ret
 	}
@@ -271,7 +271,7 @@ func (o *XmlItem) GetNameNumber() float32 {
 // GetNameNumberOk returns a tuple with the NameNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNameNumberOk() (*float32, bool) {
-	if o == nil || isNil(o.NameNumber) {
+	if o == nil || IsNil(o.NameNumber) {
 		return nil, false
 	}
 	return o.NameNumber, true
@@ -279,7 +279,7 @@ func (o *XmlItem) GetNameNumberOk() (*float32, bool) {
 
 // HasNameNumber returns a boolean if a field has been set.
 func (o *XmlItem) HasNameNumber() bool {
-	if o != nil && !isNil(o.NameNumber) {
+	if o != nil && !IsNil(o.NameNumber) {
 		return true
 	}
 
@@ -293,7 +293,7 @@ func (o *XmlItem) SetNameNumber(v float32) {
 
 // GetNameInteger returns the NameInteger field value if set, zero value otherwise.
 func (o *XmlItem) GetNameInteger() int32 {
-	if o == nil || isNil(o.NameInteger) {
+	if o == nil || IsNil(o.NameInteger) {
 		var ret int32
 		return ret
 	}
@@ -303,7 +303,7 @@ func (o *XmlItem) GetNameInteger() int32 {
 // GetNameIntegerOk returns a tuple with the NameInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNameIntegerOk() (*int32, bool) {
-	if o == nil || isNil(o.NameInteger) {
+	if o == nil || IsNil(o.NameInteger) {
 		return nil, false
 	}
 	return o.NameInteger, true
@@ -311,7 +311,7 @@ func (o *XmlItem) GetNameIntegerOk() (*int32, bool) {
 
 // HasNameInteger returns a boolean if a field has been set.
 func (o *XmlItem) HasNameInteger() bool {
-	if o != nil && !isNil(o.NameInteger) {
+	if o != nil && !IsNil(o.NameInteger) {
 		return true
 	}
 
@@ -325,7 +325,7 @@ func (o *XmlItem) SetNameInteger(v int32) {
 
 // GetNameBoolean returns the NameBoolean field value if set, zero value otherwise.
 func (o *XmlItem) GetNameBoolean() bool {
-	if o == nil || isNil(o.NameBoolean) {
+	if o == nil || IsNil(o.NameBoolean) {
 		var ret bool
 		return ret
 	}
@@ -335,7 +335,7 @@ func (o *XmlItem) GetNameBoolean() bool {
 // GetNameBooleanOk returns a tuple with the NameBoolean field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNameBooleanOk() (*bool, bool) {
-	if o == nil || isNil(o.NameBoolean) {
+	if o == nil || IsNil(o.NameBoolean) {
 		return nil, false
 	}
 	return o.NameBoolean, true
@@ -343,7 +343,7 @@ func (o *XmlItem) GetNameBooleanOk() (*bool, bool) {
 
 // HasNameBoolean returns a boolean if a field has been set.
 func (o *XmlItem) HasNameBoolean() bool {
-	if o != nil && !isNil(o.NameBoolean) {
+	if o != nil && !IsNil(o.NameBoolean) {
 		return true
 	}
 
@@ -357,7 +357,7 @@ func (o *XmlItem) SetNameBoolean(v bool) {
 
 // GetNameArray returns the NameArray field value if set, zero value otherwise.
 func (o *XmlItem) GetNameArray() []int32 {
-	if o == nil || isNil(o.NameArray) {
+	if o == nil || IsNil(o.NameArray) {
 		var ret []int32
 		return ret
 	}
@@ -367,7 +367,7 @@ func (o *XmlItem) GetNameArray() []int32 {
 // GetNameArrayOk returns a tuple with the NameArray field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNameArrayOk() ([]int32, bool) {
-	if o == nil || isNil(o.NameArray) {
+	if o == nil || IsNil(o.NameArray) {
 		return nil, false
 	}
 	return o.NameArray, true
@@ -375,7 +375,7 @@ func (o *XmlItem) GetNameArrayOk() ([]int32, bool) {
 
 // HasNameArray returns a boolean if a field has been set.
 func (o *XmlItem) HasNameArray() bool {
-	if o != nil && !isNil(o.NameArray) {
+	if o != nil && !IsNil(o.NameArray) {
 		return true
 	}
 
@@ -389,7 +389,7 @@ func (o *XmlItem) SetNameArray(v []int32) {
 
 // GetNameWrappedArray returns the NameWrappedArray field value if set, zero value otherwise.
 func (o *XmlItem) GetNameWrappedArray() []int32 {
-	if o == nil || isNil(o.NameWrappedArray) {
+	if o == nil || IsNil(o.NameWrappedArray) {
 		var ret []int32
 		return ret
 	}
@@ -399,7 +399,7 @@ func (o *XmlItem) GetNameWrappedArray() []int32 {
 // GetNameWrappedArrayOk returns a tuple with the NameWrappedArray field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNameWrappedArrayOk() ([]int32, bool) {
-	if o == nil || isNil(o.NameWrappedArray) {
+	if o == nil || IsNil(o.NameWrappedArray) {
 		return nil, false
 	}
 	return o.NameWrappedArray, true
@@ -407,7 +407,7 @@ func (o *XmlItem) GetNameWrappedArrayOk() ([]int32, bool) {
 
 // HasNameWrappedArray returns a boolean if a field has been set.
 func (o *XmlItem) HasNameWrappedArray() bool {
-	if o != nil && !isNil(o.NameWrappedArray) {
+	if o != nil && !IsNil(o.NameWrappedArray) {
 		return true
 	}
 
@@ -421,7 +421,7 @@ func (o *XmlItem) SetNameWrappedArray(v []int32) {
 
 // GetPrefixString returns the PrefixString field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixString() string {
-	if o == nil || isNil(o.PrefixString) {
+	if o == nil || IsNil(o.PrefixString) {
 		var ret string
 		return ret
 	}
@@ -431,7 +431,7 @@ func (o *XmlItem) GetPrefixString() string {
 // GetPrefixStringOk returns a tuple with the PrefixString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixStringOk() (*string, bool) {
-	if o == nil || isNil(o.PrefixString) {
+	if o == nil || IsNil(o.PrefixString) {
 		return nil, false
 	}
 	return o.PrefixString, true
@@ -439,7 +439,7 @@ func (o *XmlItem) GetPrefixStringOk() (*string, bool) {
 
 // HasPrefixString returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixString() bool {
-	if o != nil && !isNil(o.PrefixString) {
+	if o != nil && !IsNil(o.PrefixString) {
 		return true
 	}
 
@@ -453,7 +453,7 @@ func (o *XmlItem) SetPrefixString(v string) {
 
 // GetPrefixNumber returns the PrefixNumber field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixNumber() float32 {
-	if o == nil || isNil(o.PrefixNumber) {
+	if o == nil || IsNil(o.PrefixNumber) {
 		var ret float32
 		return ret
 	}
@@ -463,7 +463,7 @@ func (o *XmlItem) GetPrefixNumber() float32 {
 // GetPrefixNumberOk returns a tuple with the PrefixNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixNumberOk() (*float32, bool) {
-	if o == nil || isNil(o.PrefixNumber) {
+	if o == nil || IsNil(o.PrefixNumber) {
 		return nil, false
 	}
 	return o.PrefixNumber, true
@@ -471,7 +471,7 @@ func (o *XmlItem) GetPrefixNumberOk() (*float32, bool) {
 
 // HasPrefixNumber returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixNumber() bool {
-	if o != nil && !isNil(o.PrefixNumber) {
+	if o != nil && !IsNil(o.PrefixNumber) {
 		return true
 	}
 
@@ -485,7 +485,7 @@ func (o *XmlItem) SetPrefixNumber(v float32) {
 
 // GetPrefixInteger returns the PrefixInteger field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixInteger() int32 {
-	if o == nil || isNil(o.PrefixInteger) {
+	if o == nil || IsNil(o.PrefixInteger) {
 		var ret int32
 		return ret
 	}
@@ -495,7 +495,7 @@ func (o *XmlItem) GetPrefixInteger() int32 {
 // GetPrefixIntegerOk returns a tuple with the PrefixInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixIntegerOk() (*int32, bool) {
-	if o == nil || isNil(o.PrefixInteger) {
+	if o == nil || IsNil(o.PrefixInteger) {
 		return nil, false
 	}
 	return o.PrefixInteger, true
@@ -503,7 +503,7 @@ func (o *XmlItem) GetPrefixIntegerOk() (*int32, bool) {
 
 // HasPrefixInteger returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixInteger() bool {
-	if o != nil && !isNil(o.PrefixInteger) {
+	if o != nil && !IsNil(o.PrefixInteger) {
 		return true
 	}
 
@@ -517,7 +517,7 @@ func (o *XmlItem) SetPrefixInteger(v int32) {
 
 // GetPrefixBoolean returns the PrefixBoolean field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixBoolean() bool {
-	if o == nil || isNil(o.PrefixBoolean) {
+	if o == nil || IsNil(o.PrefixBoolean) {
 		var ret bool
 		return ret
 	}
@@ -527,7 +527,7 @@ func (o *XmlItem) GetPrefixBoolean() bool {
 // GetPrefixBooleanOk returns a tuple with the PrefixBoolean field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixBooleanOk() (*bool, bool) {
-	if o == nil || isNil(o.PrefixBoolean) {
+	if o == nil || IsNil(o.PrefixBoolean) {
 		return nil, false
 	}
 	return o.PrefixBoolean, true
@@ -535,7 +535,7 @@ func (o *XmlItem) GetPrefixBooleanOk() (*bool, bool) {
 
 // HasPrefixBoolean returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixBoolean() bool {
-	if o != nil && !isNil(o.PrefixBoolean) {
+	if o != nil && !IsNil(o.PrefixBoolean) {
 		return true
 	}
 
@@ -549,7 +549,7 @@ func (o *XmlItem) SetPrefixBoolean(v bool) {
 
 // GetPrefixArray returns the PrefixArray field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixArray() []int32 {
-	if o == nil || isNil(o.PrefixArray) {
+	if o == nil || IsNil(o.PrefixArray) {
 		var ret []int32
 		return ret
 	}
@@ -559,7 +559,7 @@ func (o *XmlItem) GetPrefixArray() []int32 {
 // GetPrefixArrayOk returns a tuple with the PrefixArray field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixArrayOk() ([]int32, bool) {
-	if o == nil || isNil(o.PrefixArray) {
+	if o == nil || IsNil(o.PrefixArray) {
 		return nil, false
 	}
 	return o.PrefixArray, true
@@ -567,7 +567,7 @@ func (o *XmlItem) GetPrefixArrayOk() ([]int32, bool) {
 
 // HasPrefixArray returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixArray() bool {
-	if o != nil && !isNil(o.PrefixArray) {
+	if o != nil && !IsNil(o.PrefixArray) {
 		return true
 	}
 
@@ -581,7 +581,7 @@ func (o *XmlItem) SetPrefixArray(v []int32) {
 
 // GetPrefixWrappedArray returns the PrefixWrappedArray field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixWrappedArray() []int32 {
-	if o == nil || isNil(o.PrefixWrappedArray) {
+	if o == nil || IsNil(o.PrefixWrappedArray) {
 		var ret []int32
 		return ret
 	}
@@ -591,7 +591,7 @@ func (o *XmlItem) GetPrefixWrappedArray() []int32 {
 // GetPrefixWrappedArrayOk returns a tuple with the PrefixWrappedArray field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixWrappedArrayOk() ([]int32, bool) {
-	if o == nil || isNil(o.PrefixWrappedArray) {
+	if o == nil || IsNil(o.PrefixWrappedArray) {
 		return nil, false
 	}
 	return o.PrefixWrappedArray, true
@@ -599,7 +599,7 @@ func (o *XmlItem) GetPrefixWrappedArrayOk() ([]int32, bool) {
 
 // HasPrefixWrappedArray returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixWrappedArray() bool {
-	if o != nil && !isNil(o.PrefixWrappedArray) {
+	if o != nil && !IsNil(o.PrefixWrappedArray) {
 		return true
 	}
 
@@ -613,7 +613,7 @@ func (o *XmlItem) SetPrefixWrappedArray(v []int32) {
 
 // GetNamespaceString returns the NamespaceString field value if set, zero value otherwise.
 func (o *XmlItem) GetNamespaceString() string {
-	if o == nil || isNil(o.NamespaceString) {
+	if o == nil || IsNil(o.NamespaceString) {
 		var ret string
 		return ret
 	}
@@ -623,7 +623,7 @@ func (o *XmlItem) GetNamespaceString() string {
 // GetNamespaceStringOk returns a tuple with the NamespaceString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNamespaceStringOk() (*string, bool) {
-	if o == nil || isNil(o.NamespaceString) {
+	if o == nil || IsNil(o.NamespaceString) {
 		return nil, false
 	}
 	return o.NamespaceString, true
@@ -631,7 +631,7 @@ func (o *XmlItem) GetNamespaceStringOk() (*string, bool) {
 
 // HasNamespaceString returns a boolean if a field has been set.
 func (o *XmlItem) HasNamespaceString() bool {
-	if o != nil && !isNil(o.NamespaceString) {
+	if o != nil && !IsNil(o.NamespaceString) {
 		return true
 	}
 
@@ -645,7 +645,7 @@ func (o *XmlItem) SetNamespaceString(v string) {
 
 // GetNamespaceNumber returns the NamespaceNumber field value if set, zero value otherwise.
 func (o *XmlItem) GetNamespaceNumber() float32 {
-	if o == nil || isNil(o.NamespaceNumber) {
+	if o == nil || IsNil(o.NamespaceNumber) {
 		var ret float32
 		return ret
 	}
@@ -655,7 +655,7 @@ func (o *XmlItem) GetNamespaceNumber() float32 {
 // GetNamespaceNumberOk returns a tuple with the NamespaceNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNamespaceNumberOk() (*float32, bool) {
-	if o == nil || isNil(o.NamespaceNumber) {
+	if o == nil || IsNil(o.NamespaceNumber) {
 		return nil, false
 	}
 	return o.NamespaceNumber, true
@@ -663,7 +663,7 @@ func (o *XmlItem) GetNamespaceNumberOk() (*float32, bool) {
 
 // HasNamespaceNumber returns a boolean if a field has been set.
 func (o *XmlItem) HasNamespaceNumber() bool {
-	if o != nil && !isNil(o.NamespaceNumber) {
+	if o != nil && !IsNil(o.NamespaceNumber) {
 		return true
 	}
 
@@ -677,7 +677,7 @@ func (o *XmlItem) SetNamespaceNumber(v float32) {
 
 // GetNamespaceInteger returns the NamespaceInteger field value if set, zero value otherwise.
 func (o *XmlItem) GetNamespaceInteger() int32 {
-	if o == nil || isNil(o.NamespaceInteger) {
+	if o == nil || IsNil(o.NamespaceInteger) {
 		var ret int32
 		return ret
 	}
@@ -687,7 +687,7 @@ func (o *XmlItem) GetNamespaceInteger() int32 {
 // GetNamespaceIntegerOk returns a tuple with the NamespaceInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNamespaceIntegerOk() (*int32, bool) {
-	if o == nil || isNil(o.NamespaceInteger) {
+	if o == nil || IsNil(o.NamespaceInteger) {
 		return nil, false
 	}
 	return o.NamespaceInteger, true
@@ -695,7 +695,7 @@ func (o *XmlItem) GetNamespaceIntegerOk() (*int32, bool) {
 
 // HasNamespaceInteger returns a boolean if a field has been set.
 func (o *XmlItem) HasNamespaceInteger() bool {
-	if o != nil && !isNil(o.NamespaceInteger) {
+	if o != nil && !IsNil(o.NamespaceInteger) {
 		return true
 	}
 
@@ -709,7 +709,7 @@ func (o *XmlItem) SetNamespaceInteger(v int32) {
 
 // GetNamespaceBoolean returns the NamespaceBoolean field value if set, zero value otherwise.
 func (o *XmlItem) GetNamespaceBoolean() bool {
-	if o == nil || isNil(o.NamespaceBoolean) {
+	if o == nil || IsNil(o.NamespaceBoolean) {
 		var ret bool
 		return ret
 	}
@@ -719,7 +719,7 @@ func (o *XmlItem) GetNamespaceBoolean() bool {
 // GetNamespaceBooleanOk returns a tuple with the NamespaceBoolean field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNamespaceBooleanOk() (*bool, bool) {
-	if o == nil || isNil(o.NamespaceBoolean) {
+	if o == nil || IsNil(o.NamespaceBoolean) {
 		return nil, false
 	}
 	return o.NamespaceBoolean, true
@@ -727,7 +727,7 @@ func (o *XmlItem) GetNamespaceBooleanOk() (*bool, bool) {
 
 // HasNamespaceBoolean returns a boolean if a field has been set.
 func (o *XmlItem) HasNamespaceBoolean() bool {
-	if o != nil && !isNil(o.NamespaceBoolean) {
+	if o != nil && !IsNil(o.NamespaceBoolean) {
 		return true
 	}
 
@@ -741,7 +741,7 @@ func (o *XmlItem) SetNamespaceBoolean(v bool) {
 
 // GetNamespaceArray returns the NamespaceArray field value if set, zero value otherwise.
 func (o *XmlItem) GetNamespaceArray() []int32 {
-	if o == nil || isNil(o.NamespaceArray) {
+	if o == nil || IsNil(o.NamespaceArray) {
 		var ret []int32
 		return ret
 	}
@@ -751,7 +751,7 @@ func (o *XmlItem) GetNamespaceArray() []int32 {
 // GetNamespaceArrayOk returns a tuple with the NamespaceArray field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNamespaceArrayOk() ([]int32, bool) {
-	if o == nil || isNil(o.NamespaceArray) {
+	if o == nil || IsNil(o.NamespaceArray) {
 		return nil, false
 	}
 	return o.NamespaceArray, true
@@ -759,7 +759,7 @@ func (o *XmlItem) GetNamespaceArrayOk() ([]int32, bool) {
 
 // HasNamespaceArray returns a boolean if a field has been set.
 func (o *XmlItem) HasNamespaceArray() bool {
-	if o != nil && !isNil(o.NamespaceArray) {
+	if o != nil && !IsNil(o.NamespaceArray) {
 		return true
 	}
 
@@ -773,7 +773,7 @@ func (o *XmlItem) SetNamespaceArray(v []int32) {
 
 // GetNamespaceWrappedArray returns the NamespaceWrappedArray field value if set, zero value otherwise.
 func (o *XmlItem) GetNamespaceWrappedArray() []int32 {
-	if o == nil || isNil(o.NamespaceWrappedArray) {
+	if o == nil || IsNil(o.NamespaceWrappedArray) {
 		var ret []int32
 		return ret
 	}
@@ -783,7 +783,7 @@ func (o *XmlItem) GetNamespaceWrappedArray() []int32 {
 // GetNamespaceWrappedArrayOk returns a tuple with the NamespaceWrappedArray field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetNamespaceWrappedArrayOk() ([]int32, bool) {
-	if o == nil || isNil(o.NamespaceWrappedArray) {
+	if o == nil || IsNil(o.NamespaceWrappedArray) {
 		return nil, false
 	}
 	return o.NamespaceWrappedArray, true
@@ -791,7 +791,7 @@ func (o *XmlItem) GetNamespaceWrappedArrayOk() ([]int32, bool) {
 
 // HasNamespaceWrappedArray returns a boolean if a field has been set.
 func (o *XmlItem) HasNamespaceWrappedArray() bool {
-	if o != nil && !isNil(o.NamespaceWrappedArray) {
+	if o != nil && !IsNil(o.NamespaceWrappedArray) {
 		return true
 	}
 
@@ -805,7 +805,7 @@ func (o *XmlItem) SetNamespaceWrappedArray(v []int32) {
 
 // GetPrefixNsString returns the PrefixNsString field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixNsString() string {
-	if o == nil || isNil(o.PrefixNsString) {
+	if o == nil || IsNil(o.PrefixNsString) {
 		var ret string
 		return ret
 	}
@@ -815,7 +815,7 @@ func (o *XmlItem) GetPrefixNsString() string {
 // GetPrefixNsStringOk returns a tuple with the PrefixNsString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixNsStringOk() (*string, bool) {
-	if o == nil || isNil(o.PrefixNsString) {
+	if o == nil || IsNil(o.PrefixNsString) {
 		return nil, false
 	}
 	return o.PrefixNsString, true
@@ -823,7 +823,7 @@ func (o *XmlItem) GetPrefixNsStringOk() (*string, bool) {
 
 // HasPrefixNsString returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixNsString() bool {
-	if o != nil && !isNil(o.PrefixNsString) {
+	if o != nil && !IsNil(o.PrefixNsString) {
 		return true
 	}
 
@@ -837,7 +837,7 @@ func (o *XmlItem) SetPrefixNsString(v string) {
 
 // GetPrefixNsNumber returns the PrefixNsNumber field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixNsNumber() float32 {
-	if o == nil || isNil(o.PrefixNsNumber) {
+	if o == nil || IsNil(o.PrefixNsNumber) {
 		var ret float32
 		return ret
 	}
@@ -847,7 +847,7 @@ func (o *XmlItem) GetPrefixNsNumber() float32 {
 // GetPrefixNsNumberOk returns a tuple with the PrefixNsNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixNsNumberOk() (*float32, bool) {
-	if o == nil || isNil(o.PrefixNsNumber) {
+	if o == nil || IsNil(o.PrefixNsNumber) {
 		return nil, false
 	}
 	return o.PrefixNsNumber, true
@@ -855,7 +855,7 @@ func (o *XmlItem) GetPrefixNsNumberOk() (*float32, bool) {
 
 // HasPrefixNsNumber returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixNsNumber() bool {
-	if o != nil && !isNil(o.PrefixNsNumber) {
+	if o != nil && !IsNil(o.PrefixNsNumber) {
 		return true
 	}
 
@@ -869,7 +869,7 @@ func (o *XmlItem) SetPrefixNsNumber(v float32) {
 
 // GetPrefixNsInteger returns the PrefixNsInteger field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixNsInteger() int32 {
-	if o == nil || isNil(o.PrefixNsInteger) {
+	if o == nil || IsNil(o.PrefixNsInteger) {
 		var ret int32
 		return ret
 	}
@@ -879,7 +879,7 @@ func (o *XmlItem) GetPrefixNsInteger() int32 {
 // GetPrefixNsIntegerOk returns a tuple with the PrefixNsInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixNsIntegerOk() (*int32, bool) {
-	if o == nil || isNil(o.PrefixNsInteger) {
+	if o == nil || IsNil(o.PrefixNsInteger) {
 		return nil, false
 	}
 	return o.PrefixNsInteger, true
@@ -887,7 +887,7 @@ func (o *XmlItem) GetPrefixNsIntegerOk() (*int32, bool) {
 
 // HasPrefixNsInteger returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixNsInteger() bool {
-	if o != nil && !isNil(o.PrefixNsInteger) {
+	if o != nil && !IsNil(o.PrefixNsInteger) {
 		return true
 	}
 
@@ -901,7 +901,7 @@ func (o *XmlItem) SetPrefixNsInteger(v int32) {
 
 // GetPrefixNsBoolean returns the PrefixNsBoolean field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixNsBoolean() bool {
-	if o == nil || isNil(o.PrefixNsBoolean) {
+	if o == nil || IsNil(o.PrefixNsBoolean) {
 		var ret bool
 		return ret
 	}
@@ -911,7 +911,7 @@ func (o *XmlItem) GetPrefixNsBoolean() bool {
 // GetPrefixNsBooleanOk returns a tuple with the PrefixNsBoolean field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixNsBooleanOk() (*bool, bool) {
-	if o == nil || isNil(o.PrefixNsBoolean) {
+	if o == nil || IsNil(o.PrefixNsBoolean) {
 		return nil, false
 	}
 	return o.PrefixNsBoolean, true
@@ -919,7 +919,7 @@ func (o *XmlItem) GetPrefixNsBooleanOk() (*bool, bool) {
 
 // HasPrefixNsBoolean returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixNsBoolean() bool {
-	if o != nil && !isNil(o.PrefixNsBoolean) {
+	if o != nil && !IsNil(o.PrefixNsBoolean) {
 		return true
 	}
 
@@ -933,7 +933,7 @@ func (o *XmlItem) SetPrefixNsBoolean(v bool) {
 
 // GetPrefixNsArray returns the PrefixNsArray field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixNsArray() []int32 {
-	if o == nil || isNil(o.PrefixNsArray) {
+	if o == nil || IsNil(o.PrefixNsArray) {
 		var ret []int32
 		return ret
 	}
@@ -943,7 +943,7 @@ func (o *XmlItem) GetPrefixNsArray() []int32 {
 // GetPrefixNsArrayOk returns a tuple with the PrefixNsArray field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixNsArrayOk() ([]int32, bool) {
-	if o == nil || isNil(o.PrefixNsArray) {
+	if o == nil || IsNil(o.PrefixNsArray) {
 		return nil, false
 	}
 	return o.PrefixNsArray, true
@@ -951,7 +951,7 @@ func (o *XmlItem) GetPrefixNsArrayOk() ([]int32, bool) {
 
 // HasPrefixNsArray returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixNsArray() bool {
-	if o != nil && !isNil(o.PrefixNsArray) {
+	if o != nil && !IsNil(o.PrefixNsArray) {
 		return true
 	}
 
@@ -965,7 +965,7 @@ func (o *XmlItem) SetPrefixNsArray(v []int32) {
 
 // GetPrefixNsWrappedArray returns the PrefixNsWrappedArray field value if set, zero value otherwise.
 func (o *XmlItem) GetPrefixNsWrappedArray() []int32 {
-	if o == nil || isNil(o.PrefixNsWrappedArray) {
+	if o == nil || IsNil(o.PrefixNsWrappedArray) {
 		var ret []int32
 		return ret
 	}
@@ -975,7 +975,7 @@ func (o *XmlItem) GetPrefixNsWrappedArray() []int32 {
 // GetPrefixNsWrappedArrayOk returns a tuple with the PrefixNsWrappedArray field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *XmlItem) GetPrefixNsWrappedArrayOk() ([]int32, bool) {
-	if o == nil || isNil(o.PrefixNsWrappedArray) {
+	if o == nil || IsNil(o.PrefixNsWrappedArray) {
 		return nil, false
 	}
 	return o.PrefixNsWrappedArray, true
@@ -983,7 +983,7 @@ func (o *XmlItem) GetPrefixNsWrappedArrayOk() ([]int32, bool) {
 
 // HasPrefixNsWrappedArray returns a boolean if a field has been set.
 func (o *XmlItem) HasPrefixNsWrappedArray() bool {
-	if o != nil && !isNil(o.PrefixNsWrappedArray) {
+	if o != nil && !IsNil(o.PrefixNsWrappedArray) {
 		return true
 	}
 
@@ -1005,91 +1005,91 @@ func (o XmlItem) MarshalJSON() ([]byte, error) {
 
 func (o XmlItem) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.AttributeString) {
+	if !IsNil(o.AttributeString) {
 		toSerialize["attribute_string"] = o.AttributeString
 	}
-	if !isNil(o.AttributeNumber) {
+	if !IsNil(o.AttributeNumber) {
 		toSerialize["attribute_number"] = o.AttributeNumber
 	}
-	if !isNil(o.AttributeInteger) {
+	if !IsNil(o.AttributeInteger) {
 		toSerialize["attribute_integer"] = o.AttributeInteger
 	}
-	if !isNil(o.AttributeBoolean) {
+	if !IsNil(o.AttributeBoolean) {
 		toSerialize["attribute_boolean"] = o.AttributeBoolean
 	}
-	if !isNil(o.WrappedArray) {
+	if !IsNil(o.WrappedArray) {
 		toSerialize["wrapped_array"] = o.WrappedArray
 	}
-	if !isNil(o.NameString) {
+	if !IsNil(o.NameString) {
 		toSerialize["name_string"] = o.NameString
 	}
-	if !isNil(o.NameNumber) {
+	if !IsNil(o.NameNumber) {
 		toSerialize["name_number"] = o.NameNumber
 	}
-	if !isNil(o.NameInteger) {
+	if !IsNil(o.NameInteger) {
 		toSerialize["name_integer"] = o.NameInteger
 	}
-	if !isNil(o.NameBoolean) {
+	if !IsNil(o.NameBoolean) {
 		toSerialize["name_boolean"] = o.NameBoolean
 	}
-	if !isNil(o.NameArray) {
+	if !IsNil(o.NameArray) {
 		toSerialize["name_array"] = o.NameArray
 	}
-	if !isNil(o.NameWrappedArray) {
+	if !IsNil(o.NameWrappedArray) {
 		toSerialize["name_wrapped_array"] = o.NameWrappedArray
 	}
-	if !isNil(o.PrefixString) {
+	if !IsNil(o.PrefixString) {
 		toSerialize["prefix_string"] = o.PrefixString
 	}
-	if !isNil(o.PrefixNumber) {
+	if !IsNil(o.PrefixNumber) {
 		toSerialize["prefix_number"] = o.PrefixNumber
 	}
-	if !isNil(o.PrefixInteger) {
+	if !IsNil(o.PrefixInteger) {
 		toSerialize["prefix_integer"] = o.PrefixInteger
 	}
-	if !isNil(o.PrefixBoolean) {
+	if !IsNil(o.PrefixBoolean) {
 		toSerialize["prefix_boolean"] = o.PrefixBoolean
 	}
-	if !isNil(o.PrefixArray) {
+	if !IsNil(o.PrefixArray) {
 		toSerialize["prefix_array"] = o.PrefixArray
 	}
-	if !isNil(o.PrefixWrappedArray) {
+	if !IsNil(o.PrefixWrappedArray) {
 		toSerialize["prefix_wrapped_array"] = o.PrefixWrappedArray
 	}
-	if !isNil(o.NamespaceString) {
+	if !IsNil(o.NamespaceString) {
 		toSerialize["namespace_string"] = o.NamespaceString
 	}
-	if !isNil(o.NamespaceNumber) {
+	if !IsNil(o.NamespaceNumber) {
 		toSerialize["namespace_number"] = o.NamespaceNumber
 	}
-	if !isNil(o.NamespaceInteger) {
+	if !IsNil(o.NamespaceInteger) {
 		toSerialize["namespace_integer"] = o.NamespaceInteger
 	}
-	if !isNil(o.NamespaceBoolean) {
+	if !IsNil(o.NamespaceBoolean) {
 		toSerialize["namespace_boolean"] = o.NamespaceBoolean
 	}
-	if !isNil(o.NamespaceArray) {
+	if !IsNil(o.NamespaceArray) {
 		toSerialize["namespace_array"] = o.NamespaceArray
 	}
-	if !isNil(o.NamespaceWrappedArray) {
+	if !IsNil(o.NamespaceWrappedArray) {
 		toSerialize["namespace_wrapped_array"] = o.NamespaceWrappedArray
 	}
-	if !isNil(o.PrefixNsString) {
+	if !IsNil(o.PrefixNsString) {
 		toSerialize["prefix_ns_string"] = o.PrefixNsString
 	}
-	if !isNil(o.PrefixNsNumber) {
+	if !IsNil(o.PrefixNsNumber) {
 		toSerialize["prefix_ns_number"] = o.PrefixNsNumber
 	}
-	if !isNil(o.PrefixNsInteger) {
+	if !IsNil(o.PrefixNsInteger) {
 		toSerialize["prefix_ns_integer"] = o.PrefixNsInteger
 	}
-	if !isNil(o.PrefixNsBoolean) {
+	if !IsNil(o.PrefixNsBoolean) {
 		toSerialize["prefix_ns_boolean"] = o.PrefixNsBoolean
 	}
-	if !isNil(o.PrefixNsArray) {
+	if !IsNil(o.PrefixNsArray) {
 		toSerialize["prefix_ns_array"] = o.PrefixNsArray
 	}
-	if !isNil(o.PrefixNsWrappedArray) {
+	if !IsNil(o.PrefixNsWrappedArray) {
 		toSerialize["prefix_ns_wrapped_array"] = o.PrefixNsWrappedArray
 	}
 	return toSerialize, nil
diff --git a/samples/client/petstore/go/go-petstore/utils.go b/samples/client/petstore/go/go-petstore/utils.go
index 9e3eb715da4..87f943e53f4 100644
--- a/samples/client/petstore/go/go-petstore/utils.go
+++ b/samples/client/petstore/go/go-petstore/utils.go
@@ -328,8 +328,8 @@ func (v *NullableTime) UnmarshalJSON(src []byte) error {
 	return json.Unmarshal(src, &v.value)
 }
 
-// isNil checks if an input is nil
-func isNil(i interface{}) bool {
+// IsNil checks if an input is nil
+func IsNil(i interface{}) bool {
 	if i == nil {
 		return true
 	}
diff --git a/samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/utils.go b/samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/utils.go
index 79c8148718b..4bb7f509c8a 100644
--- a/samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/utils.go
+++ b/samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/utils.go
@@ -328,8 +328,8 @@ func (v *NullableTime) UnmarshalJSON(src []byte) error {
 	return json.Unmarshal(src, &v.value)
 }
 
-// isNil checks if an input is nil
-func isNil(i interface{}) bool {
+// IsNil checks if an input is nil
+func IsNil(i interface{}) bool {
 	if i == nil {
 		return true
 	}
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_200_response.go b/samples/openapi3/client/petstore/go/go-petstore/model_200_response.go
index 46b818ed794..68a402cba16 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_200_response.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_200_response.go
@@ -45,7 +45,7 @@ func NewModel200ResponseWithDefaults() *Model200Response {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *Model200Response) GetName() int32 {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret int32
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *Model200Response) GetName() int32 {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Model200Response) GetNameOk() (*int32, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -63,7 +63,7 @@ func (o *Model200Response) GetNameOk() (*int32, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *Model200Response) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -77,7 +77,7 @@ func (o *Model200Response) SetName(v int32) {
 
 // GetClass returns the Class field value if set, zero value otherwise.
 func (o *Model200Response) GetClass() string {
-	if o == nil || isNil(o.Class) {
+	if o == nil || IsNil(o.Class) {
 		var ret string
 		return ret
 	}
@@ -87,7 +87,7 @@ func (o *Model200Response) GetClass() string {
 // GetClassOk returns a tuple with the Class field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Model200Response) GetClassOk() (*string, bool) {
-	if o == nil || isNil(o.Class) {
+	if o == nil || IsNil(o.Class) {
 		return nil, false
 	}
 	return o.Class, true
@@ -95,7 +95,7 @@ func (o *Model200Response) GetClassOk() (*string, bool) {
 
 // HasClass returns a boolean if a field has been set.
 func (o *Model200Response) HasClass() bool {
-	if o != nil && !isNil(o.Class) {
+	if o != nil && !IsNil(o.Class) {
 		return true
 	}
 
@@ -117,10 +117,10 @@ func (o Model200Response) MarshalJSON() ([]byte, error) {
 
 func (o Model200Response) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
-	if !isNil(o.Class) {
+	if !IsNil(o.Class) {
 		toSerialize["class"] = o.Class
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model__foo_get_default_response.go b/samples/openapi3/client/petstore/go/go-petstore/model__foo_get_default_response.go
index 07626faeb06..131bc4726e5 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model__foo_get_default_response.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model__foo_get_default_response.go
@@ -44,7 +44,7 @@ func NewFooGetDefaultResponseWithDefaults() *FooGetDefaultResponse {
 
 // GetString returns the String field value if set, zero value otherwise.
 func (o *FooGetDefaultResponse) GetString() Foo {
-	if o == nil || isNil(o.String) {
+	if o == nil || IsNil(o.String) {
 		var ret Foo
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *FooGetDefaultResponse) GetString() Foo {
 // GetStringOk returns a tuple with the String field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FooGetDefaultResponse) GetStringOk() (*Foo, bool) {
-	if o == nil || isNil(o.String) {
+	if o == nil || IsNil(o.String) {
 		return nil, false
 	}
 	return o.String, true
@@ -62,7 +62,7 @@ func (o *FooGetDefaultResponse) GetStringOk() (*Foo, bool) {
 
 // HasString returns a boolean if a field has been set.
 func (o *FooGetDefaultResponse) HasString() bool {
-	if o != nil && !isNil(o.String) {
+	if o != nil && !IsNil(o.String) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o FooGetDefaultResponse) MarshalJSON() ([]byte, error) {
 
 func (o FooGetDefaultResponse) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.String) {
+	if !IsNil(o.String) {
 		toSerialize["string"] = o.String
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model__special_model_name_.go b/samples/openapi3/client/petstore/go/go-petstore/model__special_model_name_.go
index eebad433099..55f42314057 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model__special_model_name_.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model__special_model_name_.go
@@ -44,7 +44,7 @@ func NewSpecialModelNameWithDefaults() *SpecialModelName {
 
 // GetSpecialPropertyName returns the SpecialPropertyName field value if set, zero value otherwise.
 func (o *SpecialModelName) GetSpecialPropertyName() int64 {
-	if o == nil || isNil(o.SpecialPropertyName) {
+	if o == nil || IsNil(o.SpecialPropertyName) {
 		var ret int64
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *SpecialModelName) GetSpecialPropertyName() int64 {
 // GetSpecialPropertyNameOk returns a tuple with the SpecialPropertyName field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *SpecialModelName) GetSpecialPropertyNameOk() (*int64, bool) {
-	if o == nil || isNil(o.SpecialPropertyName) {
+	if o == nil || IsNil(o.SpecialPropertyName) {
 		return nil, false
 	}
 	return o.SpecialPropertyName, true
@@ -62,7 +62,7 @@ func (o *SpecialModelName) GetSpecialPropertyNameOk() (*int64, bool) {
 
 // HasSpecialPropertyName returns a boolean if a field has been set.
 func (o *SpecialModelName) HasSpecialPropertyName() bool {
-	if o != nil && !isNil(o.SpecialPropertyName) {
+	if o != nil && !IsNil(o.SpecialPropertyName) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o SpecialModelName) MarshalJSON() ([]byte, error) {
 
 func (o SpecialModelName) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.SpecialPropertyName) {
+	if !IsNil(o.SpecialPropertyName) {
 		toSerialize["$special[property.name]"] = o.SpecialPropertyName
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_additional_properties_class.go b/samples/openapi3/client/petstore/go/go-petstore/model_additional_properties_class.go
index b2580f17a8d..bf906f2224b 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_additional_properties_class.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_additional_properties_class.go
@@ -45,7 +45,7 @@ func NewAdditionalPropertiesClassWithDefaults() *AdditionalPropertiesClass {
 
 // GetMapProperty returns the MapProperty field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetMapProperty() map[string]string {
-	if o == nil || isNil(o.MapProperty) {
+	if o == nil || IsNil(o.MapProperty) {
 		var ret map[string]string
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *AdditionalPropertiesClass) GetMapProperty() map[string]string {
 // GetMapPropertyOk returns a tuple with the MapProperty field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetMapPropertyOk() (*map[string]string, bool) {
-	if o == nil || isNil(o.MapProperty) {
+	if o == nil || IsNil(o.MapProperty) {
 		return nil, false
 	}
 	return o.MapProperty, true
@@ -63,7 +63,7 @@ func (o *AdditionalPropertiesClass) GetMapPropertyOk() (*map[string]string, bool
 
 // HasMapProperty returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasMapProperty() bool {
-	if o != nil && !isNil(o.MapProperty) {
+	if o != nil && !IsNil(o.MapProperty) {
 		return true
 	}
 
@@ -77,7 +77,7 @@ func (o *AdditionalPropertiesClass) SetMapProperty(v map[string]string) {
 
 // GetMapOfMapProperty returns the MapOfMapProperty field value if set, zero value otherwise.
 func (o *AdditionalPropertiesClass) GetMapOfMapProperty() map[string]map[string]string {
-	if o == nil || isNil(o.MapOfMapProperty) {
+	if o == nil || IsNil(o.MapOfMapProperty) {
 		var ret map[string]map[string]string
 		return ret
 	}
@@ -87,7 +87,7 @@ func (o *AdditionalPropertiesClass) GetMapOfMapProperty() map[string]map[string]
 // GetMapOfMapPropertyOk returns a tuple with the MapOfMapProperty field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AdditionalPropertiesClass) GetMapOfMapPropertyOk() (*map[string]map[string]string, bool) {
-	if o == nil || isNil(o.MapOfMapProperty) {
+	if o == nil || IsNil(o.MapOfMapProperty) {
 		return nil, false
 	}
 	return o.MapOfMapProperty, true
@@ -95,7 +95,7 @@ func (o *AdditionalPropertiesClass) GetMapOfMapPropertyOk() (*map[string]map[str
 
 // HasMapOfMapProperty returns a boolean if a field has been set.
 func (o *AdditionalPropertiesClass) HasMapOfMapProperty() bool {
-	if o != nil && !isNil(o.MapOfMapProperty) {
+	if o != nil && !IsNil(o.MapOfMapProperty) {
 		return true
 	}
 
@@ -117,10 +117,10 @@ func (o AdditionalPropertiesClass) MarshalJSON() ([]byte, error) {
 
 func (o AdditionalPropertiesClass) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.MapProperty) {
+	if !IsNil(o.MapProperty) {
 		toSerialize["map_property"] = o.MapProperty
 	}
-	if !isNil(o.MapOfMapProperty) {
+	if !IsNil(o.MapOfMapProperty) {
 		toSerialize["map_of_map_property"] = o.MapOfMapProperty
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_all_of_primitive_types.go b/samples/openapi3/client/petstore/go/go-petstore/model_all_of_primitive_types.go
index 8f4a4ca5917..825944aeadc 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_all_of_primitive_types.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_all_of_primitive_types.go
@@ -45,7 +45,7 @@ func NewAllOfPrimitiveTypesWithDefaults() *AllOfPrimitiveTypes {
 
 // GetTest returns the Test field value if set, zero value otherwise.
 func (o *AllOfPrimitiveTypes) GetTest() time.Time {
-	if o == nil || isNil(o.Test) {
+	if o == nil || IsNil(o.Test) {
 		var ret time.Time
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *AllOfPrimitiveTypes) GetTest() time.Time {
 // GetTestOk returns a tuple with the Test field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AllOfPrimitiveTypes) GetTestOk() (*time.Time, bool) {
-	if o == nil || isNil(o.Test) {
+	if o == nil || IsNil(o.Test) {
 		return nil, false
 	}
 	return o.Test, true
@@ -63,7 +63,7 @@ func (o *AllOfPrimitiveTypes) GetTestOk() (*time.Time, bool) {
 
 // HasTest returns a boolean if a field has been set.
 func (o *AllOfPrimitiveTypes) HasTest() bool {
-	if o != nil && !isNil(o.Test) {
+	if o != nil && !IsNil(o.Test) {
 		return true
 	}
 
@@ -85,7 +85,7 @@ func (o AllOfPrimitiveTypes) MarshalJSON() ([]byte, error) {
 
 func (o AllOfPrimitiveTypes) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Test) {
+	if !IsNil(o.Test) {
 		toSerialize["test"] = o.Test
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_all_of_primitive_types_all_of.go b/samples/openapi3/client/petstore/go/go-petstore/model_all_of_primitive_types_all_of.go
index 279a8e2eef1..1648becad66 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_all_of_primitive_types_all_of.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_all_of_primitive_types_all_of.go
@@ -45,7 +45,7 @@ func NewAllOfPrimitiveTypesAllOfWithDefaults() *AllOfPrimitiveTypesAllOf {
 
 // GetTest returns the Test field value if set, zero value otherwise.
 func (o *AllOfPrimitiveTypesAllOf) GetTest() time.Time {
-	if o == nil || isNil(o.Test) {
+	if o == nil || IsNil(o.Test) {
 		var ret time.Time
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *AllOfPrimitiveTypesAllOf) GetTest() time.Time {
 // GetTestOk returns a tuple with the Test field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AllOfPrimitiveTypesAllOf) GetTestOk() (*time.Time, bool) {
-	if o == nil || isNil(o.Test) {
+	if o == nil || IsNil(o.Test) {
 		return nil, false
 	}
 	return o.Test, true
@@ -63,7 +63,7 @@ func (o *AllOfPrimitiveTypesAllOf) GetTestOk() (*time.Time, bool) {
 
 // HasTest returns a boolean if a field has been set.
 func (o *AllOfPrimitiveTypesAllOf) HasTest() bool {
-	if o != nil && !isNil(o.Test) {
+	if o != nil && !IsNil(o.Test) {
 		return true
 	}
 
@@ -85,7 +85,7 @@ func (o AllOfPrimitiveTypesAllOf) MarshalJSON() ([]byte, error) {
 
 func (o AllOfPrimitiveTypesAllOf) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Test) {
+	if !IsNil(o.Test) {
 		toSerialize["test"] = o.Test
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_animal.go b/samples/openapi3/client/petstore/go/go-petstore/model_animal.go
index a550cb4223a..5b8b9b9f042 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_animal.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_animal.go
@@ -74,7 +74,7 @@ func (o *Animal) SetClassName(v string) {
 
 // GetColor returns the Color field value if set, zero value otherwise.
 func (o *Animal) GetColor() string {
-	if o == nil || isNil(o.Color) {
+	if o == nil || IsNil(o.Color) {
 		var ret string
 		return ret
 	}
@@ -84,7 +84,7 @@ func (o *Animal) GetColor() string {
 // GetColorOk returns a tuple with the Color field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Animal) GetColorOk() (*string, bool) {
-	if o == nil || isNil(o.Color) {
+	if o == nil || IsNil(o.Color) {
 		return nil, false
 	}
 	return o.Color, true
@@ -92,7 +92,7 @@ func (o *Animal) GetColorOk() (*string, bool) {
 
 // HasColor returns a boolean if a field has been set.
 func (o *Animal) HasColor() bool {
-	if o != nil && !isNil(o.Color) {
+	if o != nil && !IsNil(o.Color) {
 		return true
 	}
 
@@ -115,7 +115,7 @@ func (o Animal) MarshalJSON() ([]byte, error) {
 func (o Animal) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
 	toSerialize["className"] = o.ClassName
-	if !isNil(o.Color) {
+	if !IsNil(o.Color) {
 		toSerialize["color"] = o.Color
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_api_response.go b/samples/openapi3/client/petstore/go/go-petstore/model_api_response.go
index 363721d3f09..699ca7d52f6 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_api_response.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_api_response.go
@@ -46,7 +46,7 @@ func NewApiResponseWithDefaults() *ApiResponse {
 
 // GetCode returns the Code field value if set, zero value otherwise.
 func (o *ApiResponse) GetCode() int32 {
-	if o == nil || isNil(o.Code) {
+	if o == nil || IsNil(o.Code) {
 		var ret int32
 		return ret
 	}
@@ -56,7 +56,7 @@ func (o *ApiResponse) GetCode() int32 {
 // GetCodeOk returns a tuple with the Code field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ApiResponse) GetCodeOk() (*int32, bool) {
-	if o == nil || isNil(o.Code) {
+	if o == nil || IsNil(o.Code) {
 		return nil, false
 	}
 	return o.Code, true
@@ -64,7 +64,7 @@ func (o *ApiResponse) GetCodeOk() (*int32, bool) {
 
 // HasCode returns a boolean if a field has been set.
 func (o *ApiResponse) HasCode() bool {
-	if o != nil && !isNil(o.Code) {
+	if o != nil && !IsNil(o.Code) {
 		return true
 	}
 
@@ -78,7 +78,7 @@ func (o *ApiResponse) SetCode(v int32) {
 
 // GetType returns the Type field value if set, zero value otherwise.
 func (o *ApiResponse) GetType() string {
-	if o == nil || isNil(o.Type) {
+	if o == nil || IsNil(o.Type) {
 		var ret string
 		return ret
 	}
@@ -88,7 +88,7 @@ func (o *ApiResponse) GetType() string {
 // GetTypeOk returns a tuple with the Type field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ApiResponse) GetTypeOk() (*string, bool) {
-	if o == nil || isNil(o.Type) {
+	if o == nil || IsNil(o.Type) {
 		return nil, false
 	}
 	return o.Type, true
@@ -96,7 +96,7 @@ func (o *ApiResponse) GetTypeOk() (*string, bool) {
 
 // HasType returns a boolean if a field has been set.
 func (o *ApiResponse) HasType() bool {
-	if o != nil && !isNil(o.Type) {
+	if o != nil && !IsNil(o.Type) {
 		return true
 	}
 
@@ -110,7 +110,7 @@ func (o *ApiResponse) SetType(v string) {
 
 // GetMessage returns the Message field value if set, zero value otherwise.
 func (o *ApiResponse) GetMessage() string {
-	if o == nil || isNil(o.Message) {
+	if o == nil || IsNil(o.Message) {
 		var ret string
 		return ret
 	}
@@ -120,7 +120,7 @@ func (o *ApiResponse) GetMessage() string {
 // GetMessageOk returns a tuple with the Message field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ApiResponse) GetMessageOk() (*string, bool) {
-	if o == nil || isNil(o.Message) {
+	if o == nil || IsNil(o.Message) {
 		return nil, false
 	}
 	return o.Message, true
@@ -128,7 +128,7 @@ func (o *ApiResponse) GetMessageOk() (*string, bool) {
 
 // HasMessage returns a boolean if a field has been set.
 func (o *ApiResponse) HasMessage() bool {
-	if o != nil && !isNil(o.Message) {
+	if o != nil && !IsNil(o.Message) {
 		return true
 	}
 
@@ -150,13 +150,13 @@ func (o ApiResponse) MarshalJSON() ([]byte, error) {
 
 func (o ApiResponse) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Code) {
+	if !IsNil(o.Code) {
 		toSerialize["code"] = o.Code
 	}
-	if !isNil(o.Type) {
+	if !IsNil(o.Type) {
 		toSerialize["type"] = o.Type
 	}
-	if !isNil(o.Message) {
+	if !IsNil(o.Message) {
 		toSerialize["message"] = o.Message
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_apple.go b/samples/openapi3/client/petstore/go/go-petstore/model_apple.go
index 4e5bbfea741..43082aa35b6 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_apple.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_apple.go
@@ -44,7 +44,7 @@ func NewAppleWithDefaults() *Apple {
 
 // GetCultivar returns the Cultivar field value if set, zero value otherwise.
 func (o *Apple) GetCultivar() string {
-	if o == nil || isNil(o.Cultivar) {
+	if o == nil || IsNil(o.Cultivar) {
 		var ret string
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *Apple) GetCultivar() string {
 // GetCultivarOk returns a tuple with the Cultivar field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Apple) GetCultivarOk() (*string, bool) {
-	if o == nil || isNil(o.Cultivar) {
+	if o == nil || IsNil(o.Cultivar) {
 		return nil, false
 	}
 	return o.Cultivar, true
@@ -62,7 +62,7 @@ func (o *Apple) GetCultivarOk() (*string, bool) {
 
 // HasCultivar returns a boolean if a field has been set.
 func (o *Apple) HasCultivar() bool {
-	if o != nil && !isNil(o.Cultivar) {
+	if o != nil && !IsNil(o.Cultivar) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o Apple) MarshalJSON() ([]byte, error) {
 
 func (o Apple) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Cultivar) {
+	if !IsNil(o.Cultivar) {
 		toSerialize["cultivar"] = o.Cultivar
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_apple_req.go b/samples/openapi3/client/petstore/go/go-petstore/model_apple_req.go
index 0ceff9a111c..6e58309aa40 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_apple_req.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_apple_req.go
@@ -70,7 +70,7 @@ func (o *AppleReq) SetCultivar(v string) {
 
 // GetMealy returns the Mealy field value if set, zero value otherwise.
 func (o *AppleReq) GetMealy() bool {
-	if o == nil || isNil(o.Mealy) {
+	if o == nil || IsNil(o.Mealy) {
 		var ret bool
 		return ret
 	}
@@ -80,7 +80,7 @@ func (o *AppleReq) GetMealy() bool {
 // GetMealyOk returns a tuple with the Mealy field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *AppleReq) GetMealyOk() (*bool, bool) {
-	if o == nil || isNil(o.Mealy) {
+	if o == nil || IsNil(o.Mealy) {
 		return nil, false
 	}
 	return o.Mealy, true
@@ -88,7 +88,7 @@ func (o *AppleReq) GetMealyOk() (*bool, bool) {
 
 // HasMealy returns a boolean if a field has been set.
 func (o *AppleReq) HasMealy() bool {
-	if o != nil && !isNil(o.Mealy) {
+	if o != nil && !IsNil(o.Mealy) {
 		return true
 	}
 
@@ -111,7 +111,7 @@ func (o AppleReq) MarshalJSON() ([]byte, error) {
 func (o AppleReq) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
 	toSerialize["cultivar"] = o.Cultivar
-	if !isNil(o.Mealy) {
+	if !IsNil(o.Mealy) {
 		toSerialize["mealy"] = o.Mealy
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_array_of_array_of_number_only.go b/samples/openapi3/client/petstore/go/go-petstore/model_array_of_array_of_number_only.go
index 4356c9e2197..9f84133a4ae 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_array_of_array_of_number_only.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_array_of_array_of_number_only.go
@@ -44,7 +44,7 @@ func NewArrayOfArrayOfNumberOnlyWithDefaults() *ArrayOfArrayOfNumberOnly {
 
 // GetArrayArrayNumber returns the ArrayArrayNumber field value if set, zero value otherwise.
 func (o *ArrayOfArrayOfNumberOnly) GetArrayArrayNumber() [][]float32 {
-	if o == nil || isNil(o.ArrayArrayNumber) {
+	if o == nil || IsNil(o.ArrayArrayNumber) {
 		var ret [][]float32
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *ArrayOfArrayOfNumberOnly) GetArrayArrayNumber() [][]float32 {
 // GetArrayArrayNumberOk returns a tuple with the ArrayArrayNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ArrayOfArrayOfNumberOnly) GetArrayArrayNumberOk() ([][]float32, bool) {
-	if o == nil || isNil(o.ArrayArrayNumber) {
+	if o == nil || IsNil(o.ArrayArrayNumber) {
 		return nil, false
 	}
 	return o.ArrayArrayNumber, true
@@ -62,7 +62,7 @@ func (o *ArrayOfArrayOfNumberOnly) GetArrayArrayNumberOk() ([][]float32, bool) {
 
 // HasArrayArrayNumber returns a boolean if a field has been set.
 func (o *ArrayOfArrayOfNumberOnly) HasArrayArrayNumber() bool {
-	if o != nil && !isNil(o.ArrayArrayNumber) {
+	if o != nil && !IsNil(o.ArrayArrayNumber) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o ArrayOfArrayOfNumberOnly) MarshalJSON() ([]byte, error) {
 
 func (o ArrayOfArrayOfNumberOnly) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.ArrayArrayNumber) {
+	if !IsNil(o.ArrayArrayNumber) {
 		toSerialize["ArrayArrayNumber"] = o.ArrayArrayNumber
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_array_of_number_only.go b/samples/openapi3/client/petstore/go/go-petstore/model_array_of_number_only.go
index ce3d568ab55..e3ff1e6c56b 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_array_of_number_only.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_array_of_number_only.go
@@ -44,7 +44,7 @@ func NewArrayOfNumberOnlyWithDefaults() *ArrayOfNumberOnly {
 
 // GetArrayNumber returns the ArrayNumber field value if set, zero value otherwise.
 func (o *ArrayOfNumberOnly) GetArrayNumber() []float32 {
-	if o == nil || isNil(o.ArrayNumber) {
+	if o == nil || IsNil(o.ArrayNumber) {
 		var ret []float32
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *ArrayOfNumberOnly) GetArrayNumber() []float32 {
 // GetArrayNumberOk returns a tuple with the ArrayNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ArrayOfNumberOnly) GetArrayNumberOk() ([]float32, bool) {
-	if o == nil || isNil(o.ArrayNumber) {
+	if o == nil || IsNil(o.ArrayNumber) {
 		return nil, false
 	}
 	return o.ArrayNumber, true
@@ -62,7 +62,7 @@ func (o *ArrayOfNumberOnly) GetArrayNumberOk() ([]float32, bool) {
 
 // HasArrayNumber returns a boolean if a field has been set.
 func (o *ArrayOfNumberOnly) HasArrayNumber() bool {
-	if o != nil && !isNil(o.ArrayNumber) {
+	if o != nil && !IsNil(o.ArrayNumber) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o ArrayOfNumberOnly) MarshalJSON() ([]byte, error) {
 
 func (o ArrayOfNumberOnly) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.ArrayNumber) {
+	if !IsNil(o.ArrayNumber) {
 		toSerialize["ArrayNumber"] = o.ArrayNumber
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_array_test_.go b/samples/openapi3/client/petstore/go/go-petstore/model_array_test_.go
index 76d4ea444c9..5d97f862339 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_array_test_.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_array_test_.go
@@ -46,7 +46,7 @@ func NewArrayTestWithDefaults() *ArrayTest {
 
 // GetArrayOfString returns the ArrayOfString field value if set, zero value otherwise.
 func (o *ArrayTest) GetArrayOfString() []string {
-	if o == nil || isNil(o.ArrayOfString) {
+	if o == nil || IsNil(o.ArrayOfString) {
 		var ret []string
 		return ret
 	}
@@ -56,7 +56,7 @@ func (o *ArrayTest) GetArrayOfString() []string {
 // GetArrayOfStringOk returns a tuple with the ArrayOfString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ArrayTest) GetArrayOfStringOk() ([]string, bool) {
-	if o == nil || isNil(o.ArrayOfString) {
+	if o == nil || IsNil(o.ArrayOfString) {
 		return nil, false
 	}
 	return o.ArrayOfString, true
@@ -64,7 +64,7 @@ func (o *ArrayTest) GetArrayOfStringOk() ([]string, bool) {
 
 // HasArrayOfString returns a boolean if a field has been set.
 func (o *ArrayTest) HasArrayOfString() bool {
-	if o != nil && !isNil(o.ArrayOfString) {
+	if o != nil && !IsNil(o.ArrayOfString) {
 		return true
 	}
 
@@ -78,7 +78,7 @@ func (o *ArrayTest) SetArrayOfString(v []string) {
 
 // GetArrayArrayOfInteger returns the ArrayArrayOfInteger field value if set, zero value otherwise.
 func (o *ArrayTest) GetArrayArrayOfInteger() [][]int64 {
-	if o == nil || isNil(o.ArrayArrayOfInteger) {
+	if o == nil || IsNil(o.ArrayArrayOfInteger) {
 		var ret [][]int64
 		return ret
 	}
@@ -88,7 +88,7 @@ func (o *ArrayTest) GetArrayArrayOfInteger() [][]int64 {
 // GetArrayArrayOfIntegerOk returns a tuple with the ArrayArrayOfInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ArrayTest) GetArrayArrayOfIntegerOk() ([][]int64, bool) {
-	if o == nil || isNil(o.ArrayArrayOfInteger) {
+	if o == nil || IsNil(o.ArrayArrayOfInteger) {
 		return nil, false
 	}
 	return o.ArrayArrayOfInteger, true
@@ -96,7 +96,7 @@ func (o *ArrayTest) GetArrayArrayOfIntegerOk() ([][]int64, bool) {
 
 // HasArrayArrayOfInteger returns a boolean if a field has been set.
 func (o *ArrayTest) HasArrayArrayOfInteger() bool {
-	if o != nil && !isNil(o.ArrayArrayOfInteger) {
+	if o != nil && !IsNil(o.ArrayArrayOfInteger) {
 		return true
 	}
 
@@ -110,7 +110,7 @@ func (o *ArrayTest) SetArrayArrayOfInteger(v [][]int64) {
 
 // GetArrayArrayOfModel returns the ArrayArrayOfModel field value if set, zero value otherwise.
 func (o *ArrayTest) GetArrayArrayOfModel() [][]ReadOnlyFirst {
-	if o == nil || isNil(o.ArrayArrayOfModel) {
+	if o == nil || IsNil(o.ArrayArrayOfModel) {
 		var ret [][]ReadOnlyFirst
 		return ret
 	}
@@ -120,7 +120,7 @@ func (o *ArrayTest) GetArrayArrayOfModel() [][]ReadOnlyFirst {
 // GetArrayArrayOfModelOk returns a tuple with the ArrayArrayOfModel field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ArrayTest) GetArrayArrayOfModelOk() ([][]ReadOnlyFirst, bool) {
-	if o == nil || isNil(o.ArrayArrayOfModel) {
+	if o == nil || IsNil(o.ArrayArrayOfModel) {
 		return nil, false
 	}
 	return o.ArrayArrayOfModel, true
@@ -128,7 +128,7 @@ func (o *ArrayTest) GetArrayArrayOfModelOk() ([][]ReadOnlyFirst, bool) {
 
 // HasArrayArrayOfModel returns a boolean if a field has been set.
 func (o *ArrayTest) HasArrayArrayOfModel() bool {
-	if o != nil && !isNil(o.ArrayArrayOfModel) {
+	if o != nil && !IsNil(o.ArrayArrayOfModel) {
 		return true
 	}
 
@@ -150,13 +150,13 @@ func (o ArrayTest) MarshalJSON() ([]byte, error) {
 
 func (o ArrayTest) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.ArrayOfString) {
+	if !IsNil(o.ArrayOfString) {
 		toSerialize["array_of_string"] = o.ArrayOfString
 	}
-	if !isNil(o.ArrayArrayOfInteger) {
+	if !IsNil(o.ArrayArrayOfInteger) {
 		toSerialize["array_array_of_integer"] = o.ArrayArrayOfInteger
 	}
-	if !isNil(o.ArrayArrayOfModel) {
+	if !IsNil(o.ArrayArrayOfModel) {
 		toSerialize["array_array_of_model"] = o.ArrayArrayOfModel
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_banana.go b/samples/openapi3/client/petstore/go/go-petstore/model_banana.go
index 0a60a46712a..2a6f5d4d262 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_banana.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_banana.go
@@ -44,7 +44,7 @@ func NewBananaWithDefaults() *Banana {
 
 // GetLengthCm returns the LengthCm field value if set, zero value otherwise.
 func (o *Banana) GetLengthCm() float32 {
-	if o == nil || isNil(o.LengthCm) {
+	if o == nil || IsNil(o.LengthCm) {
 		var ret float32
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *Banana) GetLengthCm() float32 {
 // GetLengthCmOk returns a tuple with the LengthCm field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Banana) GetLengthCmOk() (*float32, bool) {
-	if o == nil || isNil(o.LengthCm) {
+	if o == nil || IsNil(o.LengthCm) {
 		return nil, false
 	}
 	return o.LengthCm, true
@@ -62,7 +62,7 @@ func (o *Banana) GetLengthCmOk() (*float32, bool) {
 
 // HasLengthCm returns a boolean if a field has been set.
 func (o *Banana) HasLengthCm() bool {
-	if o != nil && !isNil(o.LengthCm) {
+	if o != nil && !IsNil(o.LengthCm) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o Banana) MarshalJSON() ([]byte, error) {
 
 func (o Banana) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.LengthCm) {
+	if !IsNil(o.LengthCm) {
 		toSerialize["lengthCm"] = o.LengthCm
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_banana_req.go b/samples/openapi3/client/petstore/go/go-petstore/model_banana_req.go
index 79948f5f7fe..cb1045513e7 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_banana_req.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_banana_req.go
@@ -70,7 +70,7 @@ func (o *BananaReq) SetLengthCm(v float32) {
 
 // GetSweet returns the Sweet field value if set, zero value otherwise.
 func (o *BananaReq) GetSweet() bool {
-	if o == nil || isNil(o.Sweet) {
+	if o == nil || IsNil(o.Sweet) {
 		var ret bool
 		return ret
 	}
@@ -80,7 +80,7 @@ func (o *BananaReq) GetSweet() bool {
 // GetSweetOk returns a tuple with the Sweet field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *BananaReq) GetSweetOk() (*bool, bool) {
-	if o == nil || isNil(o.Sweet) {
+	if o == nil || IsNil(o.Sweet) {
 		return nil, false
 	}
 	return o.Sweet, true
@@ -88,7 +88,7 @@ func (o *BananaReq) GetSweetOk() (*bool, bool) {
 
 // HasSweet returns a boolean if a field has been set.
 func (o *BananaReq) HasSweet() bool {
-	if o != nil && !isNil(o.Sweet) {
+	if o != nil && !IsNil(o.Sweet) {
 		return true
 	}
 
@@ -111,7 +111,7 @@ func (o BananaReq) MarshalJSON() ([]byte, error) {
 func (o BananaReq) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
 	toSerialize["lengthCm"] = o.LengthCm
-	if !isNil(o.Sweet) {
+	if !IsNil(o.Sweet) {
 		toSerialize["sweet"] = o.Sweet
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_capitalization.go b/samples/openapi3/client/petstore/go/go-petstore/model_capitalization.go
index 7cbea641aa5..06a8833a2fb 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_capitalization.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_capitalization.go
@@ -50,7 +50,7 @@ func NewCapitalizationWithDefaults() *Capitalization {
 
 // GetSmallCamel returns the SmallCamel field value if set, zero value otherwise.
 func (o *Capitalization) GetSmallCamel() string {
-	if o == nil || isNil(o.SmallCamel) {
+	if o == nil || IsNil(o.SmallCamel) {
 		var ret string
 		return ret
 	}
@@ -60,7 +60,7 @@ func (o *Capitalization) GetSmallCamel() string {
 // GetSmallCamelOk returns a tuple with the SmallCamel field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetSmallCamelOk() (*string, bool) {
-	if o == nil || isNil(o.SmallCamel) {
+	if o == nil || IsNil(o.SmallCamel) {
 		return nil, false
 	}
 	return o.SmallCamel, true
@@ -68,7 +68,7 @@ func (o *Capitalization) GetSmallCamelOk() (*string, bool) {
 
 // HasSmallCamel returns a boolean if a field has been set.
 func (o *Capitalization) HasSmallCamel() bool {
-	if o != nil && !isNil(o.SmallCamel) {
+	if o != nil && !IsNil(o.SmallCamel) {
 		return true
 	}
 
@@ -82,7 +82,7 @@ func (o *Capitalization) SetSmallCamel(v string) {
 
 // GetCapitalCamel returns the CapitalCamel field value if set, zero value otherwise.
 func (o *Capitalization) GetCapitalCamel() string {
-	if o == nil || isNil(o.CapitalCamel) {
+	if o == nil || IsNil(o.CapitalCamel) {
 		var ret string
 		return ret
 	}
@@ -92,7 +92,7 @@ func (o *Capitalization) GetCapitalCamel() string {
 // GetCapitalCamelOk returns a tuple with the CapitalCamel field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetCapitalCamelOk() (*string, bool) {
-	if o == nil || isNil(o.CapitalCamel) {
+	if o == nil || IsNil(o.CapitalCamel) {
 		return nil, false
 	}
 	return o.CapitalCamel, true
@@ -100,7 +100,7 @@ func (o *Capitalization) GetCapitalCamelOk() (*string, bool) {
 
 // HasCapitalCamel returns a boolean if a field has been set.
 func (o *Capitalization) HasCapitalCamel() bool {
-	if o != nil && !isNil(o.CapitalCamel) {
+	if o != nil && !IsNil(o.CapitalCamel) {
 		return true
 	}
 
@@ -114,7 +114,7 @@ func (o *Capitalization) SetCapitalCamel(v string) {
 
 // GetSmallSnake returns the SmallSnake field value if set, zero value otherwise.
 func (o *Capitalization) GetSmallSnake() string {
-	if o == nil || isNil(o.SmallSnake) {
+	if o == nil || IsNil(o.SmallSnake) {
 		var ret string
 		return ret
 	}
@@ -124,7 +124,7 @@ func (o *Capitalization) GetSmallSnake() string {
 // GetSmallSnakeOk returns a tuple with the SmallSnake field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetSmallSnakeOk() (*string, bool) {
-	if o == nil || isNil(o.SmallSnake) {
+	if o == nil || IsNil(o.SmallSnake) {
 		return nil, false
 	}
 	return o.SmallSnake, true
@@ -132,7 +132,7 @@ func (o *Capitalization) GetSmallSnakeOk() (*string, bool) {
 
 // HasSmallSnake returns a boolean if a field has been set.
 func (o *Capitalization) HasSmallSnake() bool {
-	if o != nil && !isNil(o.SmallSnake) {
+	if o != nil && !IsNil(o.SmallSnake) {
 		return true
 	}
 
@@ -146,7 +146,7 @@ func (o *Capitalization) SetSmallSnake(v string) {
 
 // GetCapitalSnake returns the CapitalSnake field value if set, zero value otherwise.
 func (o *Capitalization) GetCapitalSnake() string {
-	if o == nil || isNil(o.CapitalSnake) {
+	if o == nil || IsNil(o.CapitalSnake) {
 		var ret string
 		return ret
 	}
@@ -156,7 +156,7 @@ func (o *Capitalization) GetCapitalSnake() string {
 // GetCapitalSnakeOk returns a tuple with the CapitalSnake field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetCapitalSnakeOk() (*string, bool) {
-	if o == nil || isNil(o.CapitalSnake) {
+	if o == nil || IsNil(o.CapitalSnake) {
 		return nil, false
 	}
 	return o.CapitalSnake, true
@@ -164,7 +164,7 @@ func (o *Capitalization) GetCapitalSnakeOk() (*string, bool) {
 
 // HasCapitalSnake returns a boolean if a field has been set.
 func (o *Capitalization) HasCapitalSnake() bool {
-	if o != nil && !isNil(o.CapitalSnake) {
+	if o != nil && !IsNil(o.CapitalSnake) {
 		return true
 	}
 
@@ -178,7 +178,7 @@ func (o *Capitalization) SetCapitalSnake(v string) {
 
 // GetSCAETHFlowPoints returns the SCAETHFlowPoints field value if set, zero value otherwise.
 func (o *Capitalization) GetSCAETHFlowPoints() string {
-	if o == nil || isNil(o.SCAETHFlowPoints) {
+	if o == nil || IsNil(o.SCAETHFlowPoints) {
 		var ret string
 		return ret
 	}
@@ -188,7 +188,7 @@ func (o *Capitalization) GetSCAETHFlowPoints() string {
 // GetSCAETHFlowPointsOk returns a tuple with the SCAETHFlowPoints field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetSCAETHFlowPointsOk() (*string, bool) {
-	if o == nil || isNil(o.SCAETHFlowPoints) {
+	if o == nil || IsNil(o.SCAETHFlowPoints) {
 		return nil, false
 	}
 	return o.SCAETHFlowPoints, true
@@ -196,7 +196,7 @@ func (o *Capitalization) GetSCAETHFlowPointsOk() (*string, bool) {
 
 // HasSCAETHFlowPoints returns a boolean if a field has been set.
 func (o *Capitalization) HasSCAETHFlowPoints() bool {
-	if o != nil && !isNil(o.SCAETHFlowPoints) {
+	if o != nil && !IsNil(o.SCAETHFlowPoints) {
 		return true
 	}
 
@@ -210,7 +210,7 @@ func (o *Capitalization) SetSCAETHFlowPoints(v string) {
 
 // GetATT_NAME returns the ATT_NAME field value if set, zero value otherwise.
 func (o *Capitalization) GetATT_NAME() string {
-	if o == nil || isNil(o.ATT_NAME) {
+	if o == nil || IsNil(o.ATT_NAME) {
 		var ret string
 		return ret
 	}
@@ -220,7 +220,7 @@ func (o *Capitalization) GetATT_NAME() string {
 // GetATT_NAMEOk returns a tuple with the ATT_NAME field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Capitalization) GetATT_NAMEOk() (*string, bool) {
-	if o == nil || isNil(o.ATT_NAME) {
+	if o == nil || IsNil(o.ATT_NAME) {
 		return nil, false
 	}
 	return o.ATT_NAME, true
@@ -228,7 +228,7 @@ func (o *Capitalization) GetATT_NAMEOk() (*string, bool) {
 
 // HasATT_NAME returns a boolean if a field has been set.
 func (o *Capitalization) HasATT_NAME() bool {
-	if o != nil && !isNil(o.ATT_NAME) {
+	if o != nil && !IsNil(o.ATT_NAME) {
 		return true
 	}
 
@@ -250,22 +250,22 @@ func (o Capitalization) MarshalJSON() ([]byte, error) {
 
 func (o Capitalization) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.SmallCamel) {
+	if !IsNil(o.SmallCamel) {
 		toSerialize["smallCamel"] = o.SmallCamel
 	}
-	if !isNil(o.CapitalCamel) {
+	if !IsNil(o.CapitalCamel) {
 		toSerialize["CapitalCamel"] = o.CapitalCamel
 	}
-	if !isNil(o.SmallSnake) {
+	if !IsNil(o.SmallSnake) {
 		toSerialize["small_Snake"] = o.SmallSnake
 	}
-	if !isNil(o.CapitalSnake) {
+	if !IsNil(o.CapitalSnake) {
 		toSerialize["Capital_Snake"] = o.CapitalSnake
 	}
-	if !isNil(o.SCAETHFlowPoints) {
+	if !IsNil(o.SCAETHFlowPoints) {
 		toSerialize["SCA_ETH_Flow_Points"] = o.SCAETHFlowPoints
 	}
-	if !isNil(o.ATT_NAME) {
+	if !IsNil(o.ATT_NAME) {
 		toSerialize["ATT_NAME"] = o.ATT_NAME
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_cat.go b/samples/openapi3/client/petstore/go/go-petstore/model_cat.go
index 45cbe81b14c..440973ad514 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_cat.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_cat.go
@@ -50,7 +50,7 @@ func NewCatWithDefaults() *Cat {
 
 // GetDeclawed returns the Declawed field value if set, zero value otherwise.
 func (o *Cat) GetDeclawed() bool {
-	if o == nil || isNil(o.Declawed) {
+	if o == nil || IsNil(o.Declawed) {
 		var ret bool
 		return ret
 	}
@@ -60,7 +60,7 @@ func (o *Cat) GetDeclawed() bool {
 // GetDeclawedOk returns a tuple with the Declawed field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Cat) GetDeclawedOk() (*bool, bool) {
-	if o == nil || isNil(o.Declawed) {
+	if o == nil || IsNil(o.Declawed) {
 		return nil, false
 	}
 	return o.Declawed, true
@@ -68,7 +68,7 @@ func (o *Cat) GetDeclawedOk() (*bool, bool) {
 
 // HasDeclawed returns a boolean if a field has been set.
 func (o *Cat) HasDeclawed() bool {
-	if o != nil && !isNil(o.Declawed) {
+	if o != nil && !IsNil(o.Declawed) {
 		return true
 	}
 
@@ -98,7 +98,7 @@ func (o Cat) ToMap() (map[string]interface{}, error) {
 	if errAnimal != nil {
 		return map[string]interface{}{}, errAnimal
 	}
-	if !isNil(o.Declawed) {
+	if !IsNil(o.Declawed) {
 		toSerialize["declawed"] = o.Declawed
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_cat_all_of.go b/samples/openapi3/client/petstore/go/go-petstore/model_cat_all_of.go
index b4d614021be..4d6bd3ebb3b 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_cat_all_of.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_cat_all_of.go
@@ -44,7 +44,7 @@ func NewCatAllOfWithDefaults() *CatAllOf {
 
 // GetDeclawed returns the Declawed field value if set, zero value otherwise.
 func (o *CatAllOf) GetDeclawed() bool {
-	if o == nil || isNil(o.Declawed) {
+	if o == nil || IsNil(o.Declawed) {
 		var ret bool
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *CatAllOf) GetDeclawed() bool {
 // GetDeclawedOk returns a tuple with the Declawed field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *CatAllOf) GetDeclawedOk() (*bool, bool) {
-	if o == nil || isNil(o.Declawed) {
+	if o == nil || IsNil(o.Declawed) {
 		return nil, false
 	}
 	return o.Declawed, true
@@ -62,7 +62,7 @@ func (o *CatAllOf) GetDeclawedOk() (*bool, bool) {
 
 // HasDeclawed returns a boolean if a field has been set.
 func (o *CatAllOf) HasDeclawed() bool {
-	if o != nil && !isNil(o.Declawed) {
+	if o != nil && !IsNil(o.Declawed) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o CatAllOf) MarshalJSON() ([]byte, error) {
 
 func (o CatAllOf) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Declawed) {
+	if !IsNil(o.Declawed) {
 		toSerialize["declawed"] = o.Declawed
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_category.go b/samples/openapi3/client/petstore/go/go-petstore/model_category.go
index edc91739855..6275a2967e9 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_category.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_category.go
@@ -48,7 +48,7 @@ func NewCategoryWithDefaults() *Category {
 
 // GetId returns the Id field value if set, zero value otherwise.
 func (o *Category) GetId() int64 {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		var ret int64
 		return ret
 	}
@@ -58,7 +58,7 @@ func (o *Category) GetId() int64 {
 // GetIdOk returns a tuple with the Id field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Category) GetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		return nil, false
 	}
 	return o.Id, true
@@ -66,7 +66,7 @@ func (o *Category) GetIdOk() (*int64, bool) {
 
 // HasId returns a boolean if a field has been set.
 func (o *Category) HasId() bool {
-	if o != nil && !isNil(o.Id) {
+	if o != nil && !IsNil(o.Id) {
 		return true
 	}
 
@@ -112,7 +112,7 @@ func (o Category) MarshalJSON() ([]byte, error) {
 
 func (o Category) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Id) {
+	if !IsNil(o.Id) {
 		toSerialize["id"] = o.Id
 	}
 	toSerialize["name"] = o.Name
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_class_model.go b/samples/openapi3/client/petstore/go/go-petstore/model_class_model.go
index c9e9015127a..0f01c820172 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_class_model.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_class_model.go
@@ -44,7 +44,7 @@ func NewClassModelWithDefaults() *ClassModel {
 
 // GetClass returns the Class field value if set, zero value otherwise.
 func (o *ClassModel) GetClass() string {
-	if o == nil || isNil(o.Class) {
+	if o == nil || IsNil(o.Class) {
 		var ret string
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *ClassModel) GetClass() string {
 // GetClassOk returns a tuple with the Class field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ClassModel) GetClassOk() (*string, bool) {
-	if o == nil || isNil(o.Class) {
+	if o == nil || IsNil(o.Class) {
 		return nil, false
 	}
 	return o.Class, true
@@ -62,7 +62,7 @@ func (o *ClassModel) GetClassOk() (*string, bool) {
 
 // HasClass returns a boolean if a field has been set.
 func (o *ClassModel) HasClass() bool {
-	if o != nil && !isNil(o.Class) {
+	if o != nil && !IsNil(o.Class) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o ClassModel) MarshalJSON() ([]byte, error) {
 
 func (o ClassModel) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Class) {
+	if !IsNil(o.Class) {
 		toSerialize["_class"] = o.Class
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_client.go b/samples/openapi3/client/petstore/go/go-petstore/model_client.go
index e50f1f84cf3..f034a9f91f2 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_client.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_client.go
@@ -44,7 +44,7 @@ func NewClientWithDefaults() *Client {
 
 // GetClient returns the Client field value if set, zero value otherwise.
 func (o *Client) GetClient() string {
-	if o == nil || isNil(o.Client) {
+	if o == nil || IsNil(o.Client) {
 		var ret string
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *Client) GetClient() string {
 // GetClientOk returns a tuple with the Client field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Client) GetClientOk() (*string, bool) {
-	if o == nil || isNil(o.Client) {
+	if o == nil || IsNil(o.Client) {
 		return nil, false
 	}
 	return o.Client, true
@@ -62,7 +62,7 @@ func (o *Client) GetClientOk() (*string, bool) {
 
 // HasClient returns a boolean if a field has been set.
 func (o *Client) HasClient() bool {
-	if o != nil && !isNil(o.Client) {
+	if o != nil && !IsNil(o.Client) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o Client) MarshalJSON() ([]byte, error) {
 
 func (o Client) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Client) {
+	if !IsNil(o.Client) {
 		toSerialize["client"] = o.Client
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_dog.go b/samples/openapi3/client/petstore/go/go-petstore/model_dog.go
index ac8ab0e7928..000bcf7e45f 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_dog.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_dog.go
@@ -50,7 +50,7 @@ func NewDogWithDefaults() *Dog {
 
 // GetBreed returns the Breed field value if set, zero value otherwise.
 func (o *Dog) GetBreed() string {
-	if o == nil || isNil(o.Breed) {
+	if o == nil || IsNil(o.Breed) {
 		var ret string
 		return ret
 	}
@@ -60,7 +60,7 @@ func (o *Dog) GetBreed() string {
 // GetBreedOk returns a tuple with the Breed field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Dog) GetBreedOk() (*string, bool) {
-	if o == nil || isNil(o.Breed) {
+	if o == nil || IsNil(o.Breed) {
 		return nil, false
 	}
 	return o.Breed, true
@@ -68,7 +68,7 @@ func (o *Dog) GetBreedOk() (*string, bool) {
 
 // HasBreed returns a boolean if a field has been set.
 func (o *Dog) HasBreed() bool {
-	if o != nil && !isNil(o.Breed) {
+	if o != nil && !IsNil(o.Breed) {
 		return true
 	}
 
@@ -98,7 +98,7 @@ func (o Dog) ToMap() (map[string]interface{}, error) {
 	if errAnimal != nil {
 		return map[string]interface{}{}, errAnimal
 	}
-	if !isNil(o.Breed) {
+	if !IsNil(o.Breed) {
 		toSerialize["breed"] = o.Breed
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_dog_all_of.go b/samples/openapi3/client/petstore/go/go-petstore/model_dog_all_of.go
index 75b73bf9391..29cced67f6d 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_dog_all_of.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_dog_all_of.go
@@ -44,7 +44,7 @@ func NewDogAllOfWithDefaults() *DogAllOf {
 
 // GetBreed returns the Breed field value if set, zero value otherwise.
 func (o *DogAllOf) GetBreed() string {
-	if o == nil || isNil(o.Breed) {
+	if o == nil || IsNil(o.Breed) {
 		var ret string
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *DogAllOf) GetBreed() string {
 // GetBreedOk returns a tuple with the Breed field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *DogAllOf) GetBreedOk() (*string, bool) {
-	if o == nil || isNil(o.Breed) {
+	if o == nil || IsNil(o.Breed) {
 		return nil, false
 	}
 	return o.Breed, true
@@ -62,7 +62,7 @@ func (o *DogAllOf) GetBreedOk() (*string, bool) {
 
 // HasBreed returns a boolean if a field has been set.
 func (o *DogAllOf) HasBreed() bool {
-	if o != nil && !isNil(o.Breed) {
+	if o != nil && !IsNil(o.Breed) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o DogAllOf) MarshalJSON() ([]byte, error) {
 
 func (o DogAllOf) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Breed) {
+	if !IsNil(o.Breed) {
 		toSerialize["breed"] = o.Breed
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_duplicated_prop_child.go b/samples/openapi3/client/petstore/go/go-petstore/model_duplicated_prop_child.go
index 277f565a5db..76a5fba804d 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_duplicated_prop_child.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_duplicated_prop_child.go
@@ -48,7 +48,7 @@ func NewDuplicatedPropChildWithDefaults() *DuplicatedPropChild {
 
 // GetDupProp returns the DupProp field value if set, zero value otherwise.
 func (o *DuplicatedPropChild) GetDupProp() string {
-	if o == nil || isNil(o.DupProp) {
+	if o == nil || IsNil(o.DupProp) {
 		var ret string
 		return ret
 	}
@@ -58,7 +58,7 @@ func (o *DuplicatedPropChild) GetDupProp() string {
 // GetDupPropOk returns a tuple with the DupProp field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *DuplicatedPropChild) GetDupPropOk() (*string, bool) {
-	if o == nil || isNil(o.DupProp) {
+	if o == nil || IsNil(o.DupProp) {
 		return nil, false
 	}
 	return o.DupProp, true
@@ -66,7 +66,7 @@ func (o *DuplicatedPropChild) GetDupPropOk() (*string, bool) {
 
 // HasDupProp returns a boolean if a field has been set.
 func (o *DuplicatedPropChild) HasDupProp() bool {
-	if o != nil && !isNil(o.DupProp) {
+	if o != nil && !IsNil(o.DupProp) {
 		return true
 	}
 
@@ -96,7 +96,7 @@ func (o DuplicatedPropChild) ToMap() (map[string]interface{}, error) {
 	if errDuplicatedPropParent != nil {
 		return map[string]interface{}{}, errDuplicatedPropParent
 	}
-	if !isNil(o.DupProp) {
+	if !IsNil(o.DupProp) {
 		toSerialize["dup-prop"] = o.DupProp
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_duplicated_prop_child_all_of.go b/samples/openapi3/client/petstore/go/go-petstore/model_duplicated_prop_child_all_of.go
index c907167df1b..615eabe4ce3 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_duplicated_prop_child_all_of.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_duplicated_prop_child_all_of.go
@@ -45,7 +45,7 @@ func NewDuplicatedPropChildAllOfWithDefaults() *DuplicatedPropChildAllOf {
 
 // GetDupProp returns the DupProp field value if set, zero value otherwise.
 func (o *DuplicatedPropChildAllOf) GetDupProp() string {
-	if o == nil || isNil(o.DupProp) {
+	if o == nil || IsNil(o.DupProp) {
 		var ret string
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *DuplicatedPropChildAllOf) GetDupProp() string {
 // GetDupPropOk returns a tuple with the DupProp field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *DuplicatedPropChildAllOf) GetDupPropOk() (*string, bool) {
-	if o == nil || isNil(o.DupProp) {
+	if o == nil || IsNil(o.DupProp) {
 		return nil, false
 	}
 	return o.DupProp, true
@@ -63,7 +63,7 @@ func (o *DuplicatedPropChildAllOf) GetDupPropOk() (*string, bool) {
 
 // HasDupProp returns a boolean if a field has been set.
 func (o *DuplicatedPropChildAllOf) HasDupProp() bool {
-	if o != nil && !isNil(o.DupProp) {
+	if o != nil && !IsNil(o.DupProp) {
 		return true
 	}
 
@@ -85,7 +85,7 @@ func (o DuplicatedPropChildAllOf) MarshalJSON() ([]byte, error) {
 
 func (o DuplicatedPropChildAllOf) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.DupProp) {
+	if !IsNil(o.DupProp) {
 		toSerialize["dup-prop"] = o.DupProp
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_enum_arrays.go b/samples/openapi3/client/petstore/go/go-petstore/model_enum_arrays.go
index abbae9a9a24..9a16611ca04 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_enum_arrays.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_enum_arrays.go
@@ -45,7 +45,7 @@ func NewEnumArraysWithDefaults() *EnumArrays {
 
 // GetJustSymbol returns the JustSymbol field value if set, zero value otherwise.
 func (o *EnumArrays) GetJustSymbol() string {
-	if o == nil || isNil(o.JustSymbol) {
+	if o == nil || IsNil(o.JustSymbol) {
 		var ret string
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *EnumArrays) GetJustSymbol() string {
 // GetJustSymbolOk returns a tuple with the JustSymbol field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumArrays) GetJustSymbolOk() (*string, bool) {
-	if o == nil || isNil(o.JustSymbol) {
+	if o == nil || IsNil(o.JustSymbol) {
 		return nil, false
 	}
 	return o.JustSymbol, true
@@ -63,7 +63,7 @@ func (o *EnumArrays) GetJustSymbolOk() (*string, bool) {
 
 // HasJustSymbol returns a boolean if a field has been set.
 func (o *EnumArrays) HasJustSymbol() bool {
-	if o != nil && !isNil(o.JustSymbol) {
+	if o != nil && !IsNil(o.JustSymbol) {
 		return true
 	}
 
@@ -77,7 +77,7 @@ func (o *EnumArrays) SetJustSymbol(v string) {
 
 // GetArrayEnum returns the ArrayEnum field value if set, zero value otherwise.
 func (o *EnumArrays) GetArrayEnum() []string {
-	if o == nil || isNil(o.ArrayEnum) {
+	if o == nil || IsNil(o.ArrayEnum) {
 		var ret []string
 		return ret
 	}
@@ -87,7 +87,7 @@ func (o *EnumArrays) GetArrayEnum() []string {
 // GetArrayEnumOk returns a tuple with the ArrayEnum field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumArrays) GetArrayEnumOk() ([]string, bool) {
-	if o == nil || isNil(o.ArrayEnum) {
+	if o == nil || IsNil(o.ArrayEnum) {
 		return nil, false
 	}
 	return o.ArrayEnum, true
@@ -95,7 +95,7 @@ func (o *EnumArrays) GetArrayEnumOk() ([]string, bool) {
 
 // HasArrayEnum returns a boolean if a field has been set.
 func (o *EnumArrays) HasArrayEnum() bool {
-	if o != nil && !isNil(o.ArrayEnum) {
+	if o != nil && !IsNil(o.ArrayEnum) {
 		return true
 	}
 
@@ -117,10 +117,10 @@ func (o EnumArrays) MarshalJSON() ([]byte, error) {
 
 func (o EnumArrays) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.JustSymbol) {
+	if !IsNil(o.JustSymbol) {
 		toSerialize["just_symbol"] = o.JustSymbol
 	}
-	if !isNil(o.ArrayEnum) {
+	if !IsNil(o.ArrayEnum) {
 		toSerialize["array_enum"] = o.ArrayEnum
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_enum_test_.go b/samples/openapi3/client/petstore/go/go-petstore/model_enum_test_.go
index 42941367b36..14202318657 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_enum_test_.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_enum_test_.go
@@ -60,7 +60,7 @@ func NewEnumTestWithDefaults() *EnumTest {
 
 // GetEnumString returns the EnumString field value if set, zero value otherwise.
 func (o *EnumTest) GetEnumString() string {
-	if o == nil || isNil(o.EnumString) {
+	if o == nil || IsNil(o.EnumString) {
 		var ret string
 		return ret
 	}
@@ -70,7 +70,7 @@ func (o *EnumTest) GetEnumString() string {
 // GetEnumStringOk returns a tuple with the EnumString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumTest) GetEnumStringOk() (*string, bool) {
-	if o == nil || isNil(o.EnumString) {
+	if o == nil || IsNil(o.EnumString) {
 		return nil, false
 	}
 	return o.EnumString, true
@@ -78,7 +78,7 @@ func (o *EnumTest) GetEnumStringOk() (*string, bool) {
 
 // HasEnumString returns a boolean if a field has been set.
 func (o *EnumTest) HasEnumString() bool {
-	if o != nil && !isNil(o.EnumString) {
+	if o != nil && !IsNil(o.EnumString) {
 		return true
 	}
 
@@ -116,7 +116,7 @@ func (o *EnumTest) SetEnumStringRequired(v string) {
 
 // GetEnumInteger returns the EnumInteger field value if set, zero value otherwise.
 func (o *EnumTest) GetEnumInteger() int32 {
-	if o == nil || isNil(o.EnumInteger) {
+	if o == nil || IsNil(o.EnumInteger) {
 		var ret int32
 		return ret
 	}
@@ -126,7 +126,7 @@ func (o *EnumTest) GetEnumInteger() int32 {
 // GetEnumIntegerOk returns a tuple with the EnumInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumTest) GetEnumIntegerOk() (*int32, bool) {
-	if o == nil || isNil(o.EnumInteger) {
+	if o == nil || IsNil(o.EnumInteger) {
 		return nil, false
 	}
 	return o.EnumInteger, true
@@ -134,7 +134,7 @@ func (o *EnumTest) GetEnumIntegerOk() (*int32, bool) {
 
 // HasEnumInteger returns a boolean if a field has been set.
 func (o *EnumTest) HasEnumInteger() bool {
-	if o != nil && !isNil(o.EnumInteger) {
+	if o != nil && !IsNil(o.EnumInteger) {
 		return true
 	}
 
@@ -148,7 +148,7 @@ func (o *EnumTest) SetEnumInteger(v int32) {
 
 // GetEnumNumber returns the EnumNumber field value if set, zero value otherwise.
 func (o *EnumTest) GetEnumNumber() float64 {
-	if o == nil || isNil(o.EnumNumber) {
+	if o == nil || IsNil(o.EnumNumber) {
 		var ret float64
 		return ret
 	}
@@ -158,7 +158,7 @@ func (o *EnumTest) GetEnumNumber() float64 {
 // GetEnumNumberOk returns a tuple with the EnumNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumTest) GetEnumNumberOk() (*float64, bool) {
-	if o == nil || isNil(o.EnumNumber) {
+	if o == nil || IsNil(o.EnumNumber) {
 		return nil, false
 	}
 	return o.EnumNumber, true
@@ -166,7 +166,7 @@ func (o *EnumTest) GetEnumNumberOk() (*float64, bool) {
 
 // HasEnumNumber returns a boolean if a field has been set.
 func (o *EnumTest) HasEnumNumber() bool {
-	if o != nil && !isNil(o.EnumNumber) {
+	if o != nil && !IsNil(o.EnumNumber) {
 		return true
 	}
 
@@ -180,7 +180,7 @@ func (o *EnumTest) SetEnumNumber(v float64) {
 
 // GetOuterEnum returns the OuterEnum field value if set, zero value otherwise (both if not set or set to explicit null).
 func (o *EnumTest) GetOuterEnum() OuterEnum {
-	if o == nil || isNil(o.OuterEnum.Get()) {
+	if o == nil || IsNil(o.OuterEnum.Get()) {
 		var ret OuterEnum
 		return ret
 	}
@@ -222,7 +222,7 @@ func (o *EnumTest) UnsetOuterEnum() {
 
 // GetOuterEnumInteger returns the OuterEnumInteger field value if set, zero value otherwise.
 func (o *EnumTest) GetOuterEnumInteger() OuterEnumInteger {
-	if o == nil || isNil(o.OuterEnumInteger) {
+	if o == nil || IsNil(o.OuterEnumInteger) {
 		var ret OuterEnumInteger
 		return ret
 	}
@@ -232,7 +232,7 @@ func (o *EnumTest) GetOuterEnumInteger() OuterEnumInteger {
 // GetOuterEnumIntegerOk returns a tuple with the OuterEnumInteger field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumTest) GetOuterEnumIntegerOk() (*OuterEnumInteger, bool) {
-	if o == nil || isNil(o.OuterEnumInteger) {
+	if o == nil || IsNil(o.OuterEnumInteger) {
 		return nil, false
 	}
 	return o.OuterEnumInteger, true
@@ -240,7 +240,7 @@ func (o *EnumTest) GetOuterEnumIntegerOk() (*OuterEnumInteger, bool) {
 
 // HasOuterEnumInteger returns a boolean if a field has been set.
 func (o *EnumTest) HasOuterEnumInteger() bool {
-	if o != nil && !isNil(o.OuterEnumInteger) {
+	if o != nil && !IsNil(o.OuterEnumInteger) {
 		return true
 	}
 
@@ -254,7 +254,7 @@ func (o *EnumTest) SetOuterEnumInteger(v OuterEnumInteger) {
 
 // GetOuterEnumDefaultValue returns the OuterEnumDefaultValue field value if set, zero value otherwise.
 func (o *EnumTest) GetOuterEnumDefaultValue() OuterEnumDefaultValue {
-	if o == nil || isNil(o.OuterEnumDefaultValue) {
+	if o == nil || IsNil(o.OuterEnumDefaultValue) {
 		var ret OuterEnumDefaultValue
 		return ret
 	}
@@ -264,7 +264,7 @@ func (o *EnumTest) GetOuterEnumDefaultValue() OuterEnumDefaultValue {
 // GetOuterEnumDefaultValueOk returns a tuple with the OuterEnumDefaultValue field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumTest) GetOuterEnumDefaultValueOk() (*OuterEnumDefaultValue, bool) {
-	if o == nil || isNil(o.OuterEnumDefaultValue) {
+	if o == nil || IsNil(o.OuterEnumDefaultValue) {
 		return nil, false
 	}
 	return o.OuterEnumDefaultValue, true
@@ -272,7 +272,7 @@ func (o *EnumTest) GetOuterEnumDefaultValueOk() (*OuterEnumDefaultValue, bool) {
 
 // HasOuterEnumDefaultValue returns a boolean if a field has been set.
 func (o *EnumTest) HasOuterEnumDefaultValue() bool {
-	if o != nil && !isNil(o.OuterEnumDefaultValue) {
+	if o != nil && !IsNil(o.OuterEnumDefaultValue) {
 		return true
 	}
 
@@ -286,7 +286,7 @@ func (o *EnumTest) SetOuterEnumDefaultValue(v OuterEnumDefaultValue) {
 
 // GetOuterEnumIntegerDefaultValue returns the OuterEnumIntegerDefaultValue field value if set, zero value otherwise.
 func (o *EnumTest) GetOuterEnumIntegerDefaultValue() OuterEnumIntegerDefaultValue {
-	if o == nil || isNil(o.OuterEnumIntegerDefaultValue) {
+	if o == nil || IsNil(o.OuterEnumIntegerDefaultValue) {
 		var ret OuterEnumIntegerDefaultValue
 		return ret
 	}
@@ -296,7 +296,7 @@ func (o *EnumTest) GetOuterEnumIntegerDefaultValue() OuterEnumIntegerDefaultValu
 // GetOuterEnumIntegerDefaultValueOk returns a tuple with the OuterEnumIntegerDefaultValue field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *EnumTest) GetOuterEnumIntegerDefaultValueOk() (*OuterEnumIntegerDefaultValue, bool) {
-	if o == nil || isNil(o.OuterEnumIntegerDefaultValue) {
+	if o == nil || IsNil(o.OuterEnumIntegerDefaultValue) {
 		return nil, false
 	}
 	return o.OuterEnumIntegerDefaultValue, true
@@ -304,7 +304,7 @@ func (o *EnumTest) GetOuterEnumIntegerDefaultValueOk() (*OuterEnumIntegerDefault
 
 // HasOuterEnumIntegerDefaultValue returns a boolean if a field has been set.
 func (o *EnumTest) HasOuterEnumIntegerDefaultValue() bool {
-	if o != nil && !isNil(o.OuterEnumIntegerDefaultValue) {
+	if o != nil && !IsNil(o.OuterEnumIntegerDefaultValue) {
 		return true
 	}
 
@@ -326,26 +326,26 @@ func (o EnumTest) MarshalJSON() ([]byte, error) {
 
 func (o EnumTest) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.EnumString) {
+	if !IsNil(o.EnumString) {
 		toSerialize["enum_string"] = o.EnumString
 	}
 	toSerialize["enum_string_required"] = o.EnumStringRequired
-	if !isNil(o.EnumInteger) {
+	if !IsNil(o.EnumInteger) {
 		toSerialize["enum_integer"] = o.EnumInteger
 	}
-	if !isNil(o.EnumNumber) {
+	if !IsNil(o.EnumNumber) {
 		toSerialize["enum_number"] = o.EnumNumber
 	}
 	if o.OuterEnum.IsSet() {
 		toSerialize["outerEnum"] = o.OuterEnum.Get()
 	}
-	if !isNil(o.OuterEnumInteger) {
+	if !IsNil(o.OuterEnumInteger) {
 		toSerialize["outerEnumInteger"] = o.OuterEnumInteger
 	}
-	if !isNil(o.OuterEnumDefaultValue) {
+	if !IsNil(o.OuterEnumDefaultValue) {
 		toSerialize["outerEnumDefaultValue"] = o.OuterEnumDefaultValue
 	}
-	if !isNil(o.OuterEnumIntegerDefaultValue) {
+	if !IsNil(o.OuterEnumIntegerDefaultValue) {
 		toSerialize["outerEnumIntegerDefaultValue"] = o.OuterEnumIntegerDefaultValue
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_file.go b/samples/openapi3/client/petstore/go/go-petstore/model_file.go
index 5d838b657ad..631cd8ee96b 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_file.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_file.go
@@ -45,7 +45,7 @@ func NewFileWithDefaults() *File {
 
 // GetSourceURI returns the SourceURI field value if set, zero value otherwise.
 func (o *File) GetSourceURI() string {
-	if o == nil || isNil(o.SourceURI) {
+	if o == nil || IsNil(o.SourceURI) {
 		var ret string
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *File) GetSourceURI() string {
 // GetSourceURIOk returns a tuple with the SourceURI field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *File) GetSourceURIOk() (*string, bool) {
-	if o == nil || isNil(o.SourceURI) {
+	if o == nil || IsNil(o.SourceURI) {
 		return nil, false
 	}
 	return o.SourceURI, true
@@ -63,7 +63,7 @@ func (o *File) GetSourceURIOk() (*string, bool) {
 
 // HasSourceURI returns a boolean if a field has been set.
 func (o *File) HasSourceURI() bool {
-	if o != nil && !isNil(o.SourceURI) {
+	if o != nil && !IsNil(o.SourceURI) {
 		return true
 	}
 
@@ -85,7 +85,7 @@ func (o File) MarshalJSON() ([]byte, error) {
 
 func (o File) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.SourceURI) {
+	if !IsNil(o.SourceURI) {
 		toSerialize["sourceURI"] = o.SourceURI
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_file_schema_test_class.go b/samples/openapi3/client/petstore/go/go-petstore/model_file_schema_test_class.go
index 6d587918ea1..d35771316bb 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_file_schema_test_class.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_file_schema_test_class.go
@@ -45,7 +45,7 @@ func NewFileSchemaTestClassWithDefaults() *FileSchemaTestClass {
 
 // GetFile returns the File field value if set, zero value otherwise.
 func (o *FileSchemaTestClass) GetFile() File {
-	if o == nil || isNil(o.File) {
+	if o == nil || IsNil(o.File) {
 		var ret File
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *FileSchemaTestClass) GetFile() File {
 // GetFileOk returns a tuple with the File field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FileSchemaTestClass) GetFileOk() (*File, bool) {
-	if o == nil || isNil(o.File) {
+	if o == nil || IsNil(o.File) {
 		return nil, false
 	}
 	return o.File, true
@@ -63,7 +63,7 @@ func (o *FileSchemaTestClass) GetFileOk() (*File, bool) {
 
 // HasFile returns a boolean if a field has been set.
 func (o *FileSchemaTestClass) HasFile() bool {
-	if o != nil && !isNil(o.File) {
+	if o != nil && !IsNil(o.File) {
 		return true
 	}
 
@@ -77,7 +77,7 @@ func (o *FileSchemaTestClass) SetFile(v File) {
 
 // GetFiles returns the Files field value if set, zero value otherwise.
 func (o *FileSchemaTestClass) GetFiles() []File {
-	if o == nil || isNil(o.Files) {
+	if o == nil || IsNil(o.Files) {
 		var ret []File
 		return ret
 	}
@@ -87,7 +87,7 @@ func (o *FileSchemaTestClass) GetFiles() []File {
 // GetFilesOk returns a tuple with the Files field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FileSchemaTestClass) GetFilesOk() ([]File, bool) {
-	if o == nil || isNil(o.Files) {
+	if o == nil || IsNil(o.Files) {
 		return nil, false
 	}
 	return o.Files, true
@@ -95,7 +95,7 @@ func (o *FileSchemaTestClass) GetFilesOk() ([]File, bool) {
 
 // HasFiles returns a boolean if a field has been set.
 func (o *FileSchemaTestClass) HasFiles() bool {
-	if o != nil && !isNil(o.Files) {
+	if o != nil && !IsNil(o.Files) {
 		return true
 	}
 
@@ -117,10 +117,10 @@ func (o FileSchemaTestClass) MarshalJSON() ([]byte, error) {
 
 func (o FileSchemaTestClass) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.File) {
+	if !IsNil(o.File) {
 		toSerialize["file"] = o.File
 	}
-	if !isNil(o.Files) {
+	if !IsNil(o.Files) {
 		toSerialize["files"] = o.Files
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_foo.go b/samples/openapi3/client/petstore/go/go-petstore/model_foo.go
index a529b9b86c5..930080a69eb 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_foo.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_foo.go
@@ -48,7 +48,7 @@ func NewFooWithDefaults() *Foo {
 
 // GetBar returns the Bar field value if set, zero value otherwise.
 func (o *Foo) GetBar() string {
-	if o == nil || isNil(o.Bar) {
+	if o == nil || IsNil(o.Bar) {
 		var ret string
 		return ret
 	}
@@ -58,7 +58,7 @@ func (o *Foo) GetBar() string {
 // GetBarOk returns a tuple with the Bar field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Foo) GetBarOk() (*string, bool) {
-	if o == nil || isNil(o.Bar) {
+	if o == nil || IsNil(o.Bar) {
 		return nil, false
 	}
 	return o.Bar, true
@@ -66,7 +66,7 @@ func (o *Foo) GetBarOk() (*string, bool) {
 
 // HasBar returns a boolean if a field has been set.
 func (o *Foo) HasBar() bool {
-	if o != nil && !isNil(o.Bar) {
+	if o != nil && !IsNil(o.Bar) {
 		return true
 	}
 
@@ -88,7 +88,7 @@ func (o Foo) MarshalJSON() ([]byte, error) {
 
 func (o Foo) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Bar) {
+	if !IsNil(o.Bar) {
 		toSerialize["bar"] = o.Bar
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_format_test_.go b/samples/openapi3/client/petstore/go/go-petstore/model_format_test_.go
index fe95d07ffaf..b887e12ec73 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_format_test_.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_format_test_.go
@@ -66,7 +66,7 @@ func NewFormatTestWithDefaults() *FormatTest {
 
 // GetInteger returns the Integer field value if set, zero value otherwise.
 func (o *FormatTest) GetInteger() int32 {
-	if o == nil || isNil(o.Integer) {
+	if o == nil || IsNil(o.Integer) {
 		var ret int32
 		return ret
 	}
@@ -76,7 +76,7 @@ func (o *FormatTest) GetInteger() int32 {
 // GetIntegerOk returns a tuple with the Integer field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetIntegerOk() (*int32, bool) {
-	if o == nil || isNil(o.Integer) {
+	if o == nil || IsNil(o.Integer) {
 		return nil, false
 	}
 	return o.Integer, true
@@ -84,7 +84,7 @@ func (o *FormatTest) GetIntegerOk() (*int32, bool) {
 
 // HasInteger returns a boolean if a field has been set.
 func (o *FormatTest) HasInteger() bool {
-	if o != nil && !isNil(o.Integer) {
+	if o != nil && !IsNil(o.Integer) {
 		return true
 	}
 
@@ -98,7 +98,7 @@ func (o *FormatTest) SetInteger(v int32) {
 
 // GetInt32 returns the Int32 field value if set, zero value otherwise.
 func (o *FormatTest) GetInt32() int32 {
-	if o == nil || isNil(o.Int32) {
+	if o == nil || IsNil(o.Int32) {
 		var ret int32
 		return ret
 	}
@@ -108,7 +108,7 @@ func (o *FormatTest) GetInt32() int32 {
 // GetInt32Ok returns a tuple with the Int32 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetInt32Ok() (*int32, bool) {
-	if o == nil || isNil(o.Int32) {
+	if o == nil || IsNil(o.Int32) {
 		return nil, false
 	}
 	return o.Int32, true
@@ -116,7 +116,7 @@ func (o *FormatTest) GetInt32Ok() (*int32, bool) {
 
 // HasInt32 returns a boolean if a field has been set.
 func (o *FormatTest) HasInt32() bool {
-	if o != nil && !isNil(o.Int32) {
+	if o != nil && !IsNil(o.Int32) {
 		return true
 	}
 
@@ -130,7 +130,7 @@ func (o *FormatTest) SetInt32(v int32) {
 
 // GetInt64 returns the Int64 field value if set, zero value otherwise.
 func (o *FormatTest) GetInt64() int64 {
-	if o == nil || isNil(o.Int64) {
+	if o == nil || IsNil(o.Int64) {
 		var ret int64
 		return ret
 	}
@@ -140,7 +140,7 @@ func (o *FormatTest) GetInt64() int64 {
 // GetInt64Ok returns a tuple with the Int64 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetInt64Ok() (*int64, bool) {
-	if o == nil || isNil(o.Int64) {
+	if o == nil || IsNil(o.Int64) {
 		return nil, false
 	}
 	return o.Int64, true
@@ -148,7 +148,7 @@ func (o *FormatTest) GetInt64Ok() (*int64, bool) {
 
 // HasInt64 returns a boolean if a field has been set.
 func (o *FormatTest) HasInt64() bool {
-	if o != nil && !isNil(o.Int64) {
+	if o != nil && !IsNil(o.Int64) {
 		return true
 	}
 
@@ -186,7 +186,7 @@ func (o *FormatTest) SetNumber(v float32) {
 
 // GetFloat returns the Float field value if set, zero value otherwise.
 func (o *FormatTest) GetFloat() float32 {
-	if o == nil || isNil(o.Float) {
+	if o == nil || IsNil(o.Float) {
 		var ret float32
 		return ret
 	}
@@ -196,7 +196,7 @@ func (o *FormatTest) GetFloat() float32 {
 // GetFloatOk returns a tuple with the Float field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetFloatOk() (*float32, bool) {
-	if o == nil || isNil(o.Float) {
+	if o == nil || IsNil(o.Float) {
 		return nil, false
 	}
 	return o.Float, true
@@ -204,7 +204,7 @@ func (o *FormatTest) GetFloatOk() (*float32, bool) {
 
 // HasFloat returns a boolean if a field has been set.
 func (o *FormatTest) HasFloat() bool {
-	if o != nil && !isNil(o.Float) {
+	if o != nil && !IsNil(o.Float) {
 		return true
 	}
 
@@ -218,7 +218,7 @@ func (o *FormatTest) SetFloat(v float32) {
 
 // GetDouble returns the Double field value if set, zero value otherwise.
 func (o *FormatTest) GetDouble() float64 {
-	if o == nil || isNil(o.Double) {
+	if o == nil || IsNil(o.Double) {
 		var ret float64
 		return ret
 	}
@@ -228,7 +228,7 @@ func (o *FormatTest) GetDouble() float64 {
 // GetDoubleOk returns a tuple with the Double field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetDoubleOk() (*float64, bool) {
-	if o == nil || isNil(o.Double) {
+	if o == nil || IsNil(o.Double) {
 		return nil, false
 	}
 	return o.Double, true
@@ -236,7 +236,7 @@ func (o *FormatTest) GetDoubleOk() (*float64, bool) {
 
 // HasDouble returns a boolean if a field has been set.
 func (o *FormatTest) HasDouble() bool {
-	if o != nil && !isNil(o.Double) {
+	if o != nil && !IsNil(o.Double) {
 		return true
 	}
 
@@ -250,7 +250,7 @@ func (o *FormatTest) SetDouble(v float64) {
 
 // GetString returns the String field value if set, zero value otherwise.
 func (o *FormatTest) GetString() string {
-	if o == nil || isNil(o.String) {
+	if o == nil || IsNil(o.String) {
 		var ret string
 		return ret
 	}
@@ -260,7 +260,7 @@ func (o *FormatTest) GetString() string {
 // GetStringOk returns a tuple with the String field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetStringOk() (*string, bool) {
-	if o == nil || isNil(o.String) {
+	if o == nil || IsNil(o.String) {
 		return nil, false
 	}
 	return o.String, true
@@ -268,7 +268,7 @@ func (o *FormatTest) GetStringOk() (*string, bool) {
 
 // HasString returns a boolean if a field has been set.
 func (o *FormatTest) HasString() bool {
-	if o != nil && !isNil(o.String) {
+	if o != nil && !IsNil(o.String) {
 		return true
 	}
 
@@ -306,7 +306,7 @@ func (o *FormatTest) SetByte(v string) {
 
 // GetBinary returns the Binary field value if set, zero value otherwise.
 func (o *FormatTest) GetBinary() *os.File {
-	if o == nil || isNil(o.Binary) {
+	if o == nil || IsNil(o.Binary) {
 		var ret *os.File
 		return ret
 	}
@@ -316,7 +316,7 @@ func (o *FormatTest) GetBinary() *os.File {
 // GetBinaryOk returns a tuple with the Binary field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetBinaryOk() (**os.File, bool) {
-	if o == nil || isNil(o.Binary) {
+	if o == nil || IsNil(o.Binary) {
 		return nil, false
 	}
 	return o.Binary, true
@@ -324,7 +324,7 @@ func (o *FormatTest) GetBinaryOk() (**os.File, bool) {
 
 // HasBinary returns a boolean if a field has been set.
 func (o *FormatTest) HasBinary() bool {
-	if o != nil && !isNil(o.Binary) {
+	if o != nil && !IsNil(o.Binary) {
 		return true
 	}
 
@@ -362,7 +362,7 @@ func (o *FormatTest) SetDate(v string) {
 
 // GetDateTime returns the DateTime field value if set, zero value otherwise.
 func (o *FormatTest) GetDateTime() time.Time {
-	if o == nil || isNil(o.DateTime) {
+	if o == nil || IsNil(o.DateTime) {
 		var ret time.Time
 		return ret
 	}
@@ -372,7 +372,7 @@ func (o *FormatTest) GetDateTime() time.Time {
 // GetDateTimeOk returns a tuple with the DateTime field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetDateTimeOk() (*time.Time, bool) {
-	if o == nil || isNil(o.DateTime) {
+	if o == nil || IsNil(o.DateTime) {
 		return nil, false
 	}
 	return o.DateTime, true
@@ -380,7 +380,7 @@ func (o *FormatTest) GetDateTimeOk() (*time.Time, bool) {
 
 // HasDateTime returns a boolean if a field has been set.
 func (o *FormatTest) HasDateTime() bool {
-	if o != nil && !isNil(o.DateTime) {
+	if o != nil && !IsNil(o.DateTime) {
 		return true
 	}
 
@@ -394,7 +394,7 @@ func (o *FormatTest) SetDateTime(v time.Time) {
 
 // GetUuid returns the Uuid field value if set, zero value otherwise.
 func (o *FormatTest) GetUuid() string {
-	if o == nil || isNil(o.Uuid) {
+	if o == nil || IsNil(o.Uuid) {
 		var ret string
 		return ret
 	}
@@ -404,7 +404,7 @@ func (o *FormatTest) GetUuid() string {
 // GetUuidOk returns a tuple with the Uuid field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetUuidOk() (*string, bool) {
-	if o == nil || isNil(o.Uuid) {
+	if o == nil || IsNil(o.Uuid) {
 		return nil, false
 	}
 	return o.Uuid, true
@@ -412,7 +412,7 @@ func (o *FormatTest) GetUuidOk() (*string, bool) {
 
 // HasUuid returns a boolean if a field has been set.
 func (o *FormatTest) HasUuid() bool {
-	if o != nil && !isNil(o.Uuid) {
+	if o != nil && !IsNil(o.Uuid) {
 		return true
 	}
 
@@ -450,7 +450,7 @@ func (o *FormatTest) SetPassword(v string) {
 
 // GetPatternWithDigits returns the PatternWithDigits field value if set, zero value otherwise.
 func (o *FormatTest) GetPatternWithDigits() string {
-	if o == nil || isNil(o.PatternWithDigits) {
+	if o == nil || IsNil(o.PatternWithDigits) {
 		var ret string
 		return ret
 	}
@@ -460,7 +460,7 @@ func (o *FormatTest) GetPatternWithDigits() string {
 // GetPatternWithDigitsOk returns a tuple with the PatternWithDigits field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetPatternWithDigitsOk() (*string, bool) {
-	if o == nil || isNil(o.PatternWithDigits) {
+	if o == nil || IsNil(o.PatternWithDigits) {
 		return nil, false
 	}
 	return o.PatternWithDigits, true
@@ -468,7 +468,7 @@ func (o *FormatTest) GetPatternWithDigitsOk() (*string, bool) {
 
 // HasPatternWithDigits returns a boolean if a field has been set.
 func (o *FormatTest) HasPatternWithDigits() bool {
-	if o != nil && !isNil(o.PatternWithDigits) {
+	if o != nil && !IsNil(o.PatternWithDigits) {
 		return true
 	}
 
@@ -482,7 +482,7 @@ func (o *FormatTest) SetPatternWithDigits(v string) {
 
 // GetPatternWithDigitsAndDelimiter returns the PatternWithDigitsAndDelimiter field value if set, zero value otherwise.
 func (o *FormatTest) GetPatternWithDigitsAndDelimiter() string {
-	if o == nil || isNil(o.PatternWithDigitsAndDelimiter) {
+	if o == nil || IsNil(o.PatternWithDigitsAndDelimiter) {
 		var ret string
 		return ret
 	}
@@ -492,7 +492,7 @@ func (o *FormatTest) GetPatternWithDigitsAndDelimiter() string {
 // GetPatternWithDigitsAndDelimiterOk returns a tuple with the PatternWithDigitsAndDelimiter field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *FormatTest) GetPatternWithDigitsAndDelimiterOk() (*string, bool) {
-	if o == nil || isNil(o.PatternWithDigitsAndDelimiter) {
+	if o == nil || IsNil(o.PatternWithDigitsAndDelimiter) {
 		return nil, false
 	}
 	return o.PatternWithDigitsAndDelimiter, true
@@ -500,7 +500,7 @@ func (o *FormatTest) GetPatternWithDigitsAndDelimiterOk() (*string, bool) {
 
 // HasPatternWithDigitsAndDelimiter returns a boolean if a field has been set.
 func (o *FormatTest) HasPatternWithDigitsAndDelimiter() bool {
-	if o != nil && !isNil(o.PatternWithDigitsAndDelimiter) {
+	if o != nil && !IsNil(o.PatternWithDigitsAndDelimiter) {
 		return true
 	}
 
@@ -522,41 +522,41 @@ func (o FormatTest) MarshalJSON() ([]byte, error) {
 
 func (o FormatTest) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Integer) {
+	if !IsNil(o.Integer) {
 		toSerialize["integer"] = o.Integer
 	}
-	if !isNil(o.Int32) {
+	if !IsNil(o.Int32) {
 		toSerialize["int32"] = o.Int32
 	}
-	if !isNil(o.Int64) {
+	if !IsNil(o.Int64) {
 		toSerialize["int64"] = o.Int64
 	}
 	toSerialize["number"] = o.Number
-	if !isNil(o.Float) {
+	if !IsNil(o.Float) {
 		toSerialize["float"] = o.Float
 	}
-	if !isNil(o.Double) {
+	if !IsNil(o.Double) {
 		toSerialize["double"] = o.Double
 	}
-	if !isNil(o.String) {
+	if !IsNil(o.String) {
 		toSerialize["string"] = o.String
 	}
 	toSerialize["byte"] = o.Byte
-	if !isNil(o.Binary) {
+	if !IsNil(o.Binary) {
 		toSerialize["binary"] = o.Binary
 	}
 	toSerialize["date"] = o.Date
-	if !isNil(o.DateTime) {
+	if !IsNil(o.DateTime) {
 		toSerialize["dateTime"] = o.DateTime
 	}
-	if !isNil(o.Uuid) {
+	if !IsNil(o.Uuid) {
 		toSerialize["uuid"] = o.Uuid
 	}
 	toSerialize["password"] = o.Password
-	if !isNil(o.PatternWithDigits) {
+	if !IsNil(o.PatternWithDigits) {
 		toSerialize["pattern_with_digits"] = o.PatternWithDigits
 	}
-	if !isNil(o.PatternWithDigitsAndDelimiter) {
+	if !IsNil(o.PatternWithDigitsAndDelimiter) {
 		toSerialize["pattern_with_digits_and_delimiter"] = o.PatternWithDigitsAndDelimiter
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_has_only_read_only.go b/samples/openapi3/client/petstore/go/go-petstore/model_has_only_read_only.go
index 31f17906d08..42a5caae896 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_has_only_read_only.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_has_only_read_only.go
@@ -45,7 +45,7 @@ func NewHasOnlyReadOnlyWithDefaults() *HasOnlyReadOnly {
 
 // GetBar returns the Bar field value if set, zero value otherwise.
 func (o *HasOnlyReadOnly) GetBar() string {
-	if o == nil || isNil(o.Bar) {
+	if o == nil || IsNil(o.Bar) {
 		var ret string
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *HasOnlyReadOnly) GetBar() string {
 // GetBarOk returns a tuple with the Bar field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *HasOnlyReadOnly) GetBarOk() (*string, bool) {
-	if o == nil || isNil(o.Bar) {
+	if o == nil || IsNil(o.Bar) {
 		return nil, false
 	}
 	return o.Bar, true
@@ -63,7 +63,7 @@ func (o *HasOnlyReadOnly) GetBarOk() (*string, bool) {
 
 // HasBar returns a boolean if a field has been set.
 func (o *HasOnlyReadOnly) HasBar() bool {
-	if o != nil && !isNil(o.Bar) {
+	if o != nil && !IsNil(o.Bar) {
 		return true
 	}
 
@@ -77,7 +77,7 @@ func (o *HasOnlyReadOnly) SetBar(v string) {
 
 // GetFoo returns the Foo field value if set, zero value otherwise.
 func (o *HasOnlyReadOnly) GetFoo() string {
-	if o == nil || isNil(o.Foo) {
+	if o == nil || IsNil(o.Foo) {
 		var ret string
 		return ret
 	}
@@ -87,7 +87,7 @@ func (o *HasOnlyReadOnly) GetFoo() string {
 // GetFooOk returns a tuple with the Foo field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *HasOnlyReadOnly) GetFooOk() (*string, bool) {
-	if o == nil || isNil(o.Foo) {
+	if o == nil || IsNil(o.Foo) {
 		return nil, false
 	}
 	return o.Foo, true
@@ -95,7 +95,7 @@ func (o *HasOnlyReadOnly) GetFooOk() (*string, bool) {
 
 // HasFoo returns a boolean if a field has been set.
 func (o *HasOnlyReadOnly) HasFoo() bool {
-	if o != nil && !isNil(o.Foo) {
+	if o != nil && !IsNil(o.Foo) {
 		return true
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_health_check_result.go b/samples/openapi3/client/petstore/go/go-petstore/model_health_check_result.go
index 4338603ff86..c3498f9e9f8 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_health_check_result.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_health_check_result.go
@@ -44,7 +44,7 @@ func NewHealthCheckResultWithDefaults() *HealthCheckResult {
 
 // GetNullableMessage returns the NullableMessage field value if set, zero value otherwise (both if not set or set to explicit null).
 func (o *HealthCheckResult) GetNullableMessage() string {
-	if o == nil || isNil(o.NullableMessage.Get()) {
+	if o == nil || IsNil(o.NullableMessage.Get()) {
 		var ret string
 		return ret
 	}
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_list.go b/samples/openapi3/client/petstore/go/go-petstore/model_list.go
index 0be0312e32e..77017d73bc0 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_list.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_list.go
@@ -44,7 +44,7 @@ func NewListWithDefaults() *List {
 
 // GetVar123List returns the Var123List field value if set, zero value otherwise.
 func (o *List) GetVar123List() string {
-	if o == nil || isNil(o.Var123List) {
+	if o == nil || IsNil(o.Var123List) {
 		var ret string
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *List) GetVar123List() string {
 // GetVar123ListOk returns a tuple with the Var123List field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *List) GetVar123ListOk() (*string, bool) {
-	if o == nil || isNil(o.Var123List) {
+	if o == nil || IsNil(o.Var123List) {
 		return nil, false
 	}
 	return o.Var123List, true
@@ -62,7 +62,7 @@ func (o *List) GetVar123ListOk() (*string, bool) {
 
 // HasVar123List returns a boolean if a field has been set.
 func (o *List) HasVar123List() bool {
-	if o != nil && !isNil(o.Var123List) {
+	if o != nil && !IsNil(o.Var123List) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o List) MarshalJSON() ([]byte, error) {
 
 func (o List) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Var123List) {
+	if !IsNil(o.Var123List) {
 		toSerialize["123-list"] = o.Var123List
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_map_of_file_test_.go b/samples/openapi3/client/petstore/go/go-petstore/model_map_of_file_test_.go
index a96502e0847..e14eaaafe24 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_map_of_file_test_.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_map_of_file_test_.go
@@ -46,7 +46,7 @@ func NewMapOfFileTestWithDefaults() *MapOfFileTest {
 
 // GetPropTest returns the PropTest field value if set, zero value otherwise.
 func (o *MapOfFileTest) GetPropTest() map[string]*os.File {
-	if o == nil || isNil(o.PropTest) {
+	if o == nil || IsNil(o.PropTest) {
 		var ret map[string]*os.File
 		return ret
 	}
@@ -56,7 +56,7 @@ func (o *MapOfFileTest) GetPropTest() map[string]*os.File {
 // GetPropTestOk returns a tuple with the PropTest field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MapOfFileTest) GetPropTestOk() (*map[string]*os.File, bool) {
-	if o == nil || isNil(o.PropTest) {
+	if o == nil || IsNil(o.PropTest) {
 		return nil, false
 	}
 	return o.PropTest, true
@@ -64,7 +64,7 @@ func (o *MapOfFileTest) GetPropTestOk() (*map[string]*os.File, bool) {
 
 // HasPropTest returns a boolean if a field has been set.
 func (o *MapOfFileTest) HasPropTest() bool {
-	if o != nil && !isNil(o.PropTest) {
+	if o != nil && !IsNil(o.PropTest) {
 		return true
 	}
 
@@ -86,7 +86,7 @@ func (o MapOfFileTest) MarshalJSON() ([]byte, error) {
 
 func (o MapOfFileTest) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.PropTest) {
+	if !IsNil(o.PropTest) {
 		toSerialize["prop_test"] = o.PropTest
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_map_test_.go b/samples/openapi3/client/petstore/go/go-petstore/model_map_test_.go
index 2f8a6f6371d..bd512760a45 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_map_test_.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_map_test_.go
@@ -47,7 +47,7 @@ func NewMapTestWithDefaults() *MapTest {
 
 // GetMapMapOfString returns the MapMapOfString field value if set, zero value otherwise.
 func (o *MapTest) GetMapMapOfString() map[string]map[string]string {
-	if o == nil || isNil(o.MapMapOfString) {
+	if o == nil || IsNil(o.MapMapOfString) {
 		var ret map[string]map[string]string
 		return ret
 	}
@@ -57,7 +57,7 @@ func (o *MapTest) GetMapMapOfString() map[string]map[string]string {
 // GetMapMapOfStringOk returns a tuple with the MapMapOfString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MapTest) GetMapMapOfStringOk() (*map[string]map[string]string, bool) {
-	if o == nil || isNil(o.MapMapOfString) {
+	if o == nil || IsNil(o.MapMapOfString) {
 		return nil, false
 	}
 	return o.MapMapOfString, true
@@ -65,7 +65,7 @@ func (o *MapTest) GetMapMapOfStringOk() (*map[string]map[string]string, bool) {
 
 // HasMapMapOfString returns a boolean if a field has been set.
 func (o *MapTest) HasMapMapOfString() bool {
-	if o != nil && !isNil(o.MapMapOfString) {
+	if o != nil && !IsNil(o.MapMapOfString) {
 		return true
 	}
 
@@ -79,7 +79,7 @@ func (o *MapTest) SetMapMapOfString(v map[string]map[string]string) {
 
 // GetMapOfEnumString returns the MapOfEnumString field value if set, zero value otherwise.
 func (o *MapTest) GetMapOfEnumString() map[string]string {
-	if o == nil || isNil(o.MapOfEnumString) {
+	if o == nil || IsNil(o.MapOfEnumString) {
 		var ret map[string]string
 		return ret
 	}
@@ -89,7 +89,7 @@ func (o *MapTest) GetMapOfEnumString() map[string]string {
 // GetMapOfEnumStringOk returns a tuple with the MapOfEnumString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MapTest) GetMapOfEnumStringOk() (*map[string]string, bool) {
-	if o == nil || isNil(o.MapOfEnumString) {
+	if o == nil || IsNil(o.MapOfEnumString) {
 		return nil, false
 	}
 	return o.MapOfEnumString, true
@@ -97,7 +97,7 @@ func (o *MapTest) GetMapOfEnumStringOk() (*map[string]string, bool) {
 
 // HasMapOfEnumString returns a boolean if a field has been set.
 func (o *MapTest) HasMapOfEnumString() bool {
-	if o != nil && !isNil(o.MapOfEnumString) {
+	if o != nil && !IsNil(o.MapOfEnumString) {
 		return true
 	}
 
@@ -111,7 +111,7 @@ func (o *MapTest) SetMapOfEnumString(v map[string]string) {
 
 // GetDirectMap returns the DirectMap field value if set, zero value otherwise.
 func (o *MapTest) GetDirectMap() map[string]bool {
-	if o == nil || isNil(o.DirectMap) {
+	if o == nil || IsNil(o.DirectMap) {
 		var ret map[string]bool
 		return ret
 	}
@@ -121,7 +121,7 @@ func (o *MapTest) GetDirectMap() map[string]bool {
 // GetDirectMapOk returns a tuple with the DirectMap field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MapTest) GetDirectMapOk() (*map[string]bool, bool) {
-	if o == nil || isNil(o.DirectMap) {
+	if o == nil || IsNil(o.DirectMap) {
 		return nil, false
 	}
 	return o.DirectMap, true
@@ -129,7 +129,7 @@ func (o *MapTest) GetDirectMapOk() (*map[string]bool, bool) {
 
 // HasDirectMap returns a boolean if a field has been set.
 func (o *MapTest) HasDirectMap() bool {
-	if o != nil && !isNil(o.DirectMap) {
+	if o != nil && !IsNil(o.DirectMap) {
 		return true
 	}
 
@@ -143,7 +143,7 @@ func (o *MapTest) SetDirectMap(v map[string]bool) {
 
 // GetIndirectMap returns the IndirectMap field value if set, zero value otherwise.
 func (o *MapTest) GetIndirectMap() map[string]bool {
-	if o == nil || isNil(o.IndirectMap) {
+	if o == nil || IsNil(o.IndirectMap) {
 		var ret map[string]bool
 		return ret
 	}
@@ -153,7 +153,7 @@ func (o *MapTest) GetIndirectMap() map[string]bool {
 // GetIndirectMapOk returns a tuple with the IndirectMap field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MapTest) GetIndirectMapOk() (*map[string]bool, bool) {
-	if o == nil || isNil(o.IndirectMap) {
+	if o == nil || IsNil(o.IndirectMap) {
 		return nil, false
 	}
 	return o.IndirectMap, true
@@ -161,7 +161,7 @@ func (o *MapTest) GetIndirectMapOk() (*map[string]bool, bool) {
 
 // HasIndirectMap returns a boolean if a field has been set.
 func (o *MapTest) HasIndirectMap() bool {
-	if o != nil && !isNil(o.IndirectMap) {
+	if o != nil && !IsNil(o.IndirectMap) {
 		return true
 	}
 
@@ -183,16 +183,16 @@ func (o MapTest) MarshalJSON() ([]byte, error) {
 
 func (o MapTest) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.MapMapOfString) {
+	if !IsNil(o.MapMapOfString) {
 		toSerialize["map_map_of_string"] = o.MapMapOfString
 	}
-	if !isNil(o.MapOfEnumString) {
+	if !IsNil(o.MapOfEnumString) {
 		toSerialize["map_of_enum_string"] = o.MapOfEnumString
 	}
-	if !isNil(o.DirectMap) {
+	if !IsNil(o.DirectMap) {
 		toSerialize["direct_map"] = o.DirectMap
 	}
-	if !isNil(o.IndirectMap) {
+	if !IsNil(o.IndirectMap) {
 		toSerialize["indirect_map"] = o.IndirectMap
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_mixed_properties_and_additional_properties_class.go b/samples/openapi3/client/petstore/go/go-petstore/model_mixed_properties_and_additional_properties_class.go
index 5034ef2bc92..4a65bb99573 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_mixed_properties_and_additional_properties_class.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_mixed_properties_and_additional_properties_class.go
@@ -47,7 +47,7 @@ func NewMixedPropertiesAndAdditionalPropertiesClassWithDefaults() *MixedProperti
 
 // GetUuid returns the Uuid field value if set, zero value otherwise.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetUuid() string {
-	if o == nil || isNil(o.Uuid) {
+	if o == nil || IsNil(o.Uuid) {
 		var ret string
 		return ret
 	}
@@ -57,7 +57,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetUuid() string {
 // GetUuidOk returns a tuple with the Uuid field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetUuidOk() (*string, bool) {
-	if o == nil || isNil(o.Uuid) {
+	if o == nil || IsNil(o.Uuid) {
 		return nil, false
 	}
 	return o.Uuid, true
@@ -65,7 +65,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetUuidOk() (*string, bool
 
 // HasUuid returns a boolean if a field has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) HasUuid() bool {
-	if o != nil && !isNil(o.Uuid) {
+	if o != nil && !IsNil(o.Uuid) {
 		return true
 	}
 
@@ -79,7 +79,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) SetUuid(v string) {
 
 // GetDateTime returns the DateTime field value if set, zero value otherwise.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetDateTime() time.Time {
-	if o == nil || isNil(o.DateTime) {
+	if o == nil || IsNil(o.DateTime) {
 		var ret time.Time
 		return ret
 	}
@@ -89,7 +89,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetDateTime() time.Time {
 // GetDateTimeOk returns a tuple with the DateTime field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetDateTimeOk() (*time.Time, bool) {
-	if o == nil || isNil(o.DateTime) {
+	if o == nil || IsNil(o.DateTime) {
 		return nil, false
 	}
 	return o.DateTime, true
@@ -97,7 +97,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetDateTimeOk() (*time.Tim
 
 // HasDateTime returns a boolean if a field has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) HasDateTime() bool {
-	if o != nil && !isNil(o.DateTime) {
+	if o != nil && !IsNil(o.DateTime) {
 		return true
 	}
 
@@ -111,7 +111,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) SetDateTime(v time.Time) {
 
 // GetMap returns the Map field value if set, zero value otherwise.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetMap() map[string]Animal {
-	if o == nil || isNil(o.Map) {
+	if o == nil || IsNil(o.Map) {
 		var ret map[string]Animal
 		return ret
 	}
@@ -121,7 +121,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetMap() map[string]Animal
 // GetMapOk returns a tuple with the Map field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) GetMapOk() (*map[string]Animal, bool) {
-	if o == nil || isNil(o.Map) {
+	if o == nil || IsNil(o.Map) {
 		return nil, false
 	}
 	return o.Map, true
@@ -129,7 +129,7 @@ func (o *MixedPropertiesAndAdditionalPropertiesClass) GetMapOk() (*map[string]An
 
 // HasMap returns a boolean if a field has been set.
 func (o *MixedPropertiesAndAdditionalPropertiesClass) HasMap() bool {
-	if o != nil && !isNil(o.Map) {
+	if o != nil && !IsNil(o.Map) {
 		return true
 	}
 
@@ -151,13 +151,13 @@ func (o MixedPropertiesAndAdditionalPropertiesClass) MarshalJSON() ([]byte, erro
 
 func (o MixedPropertiesAndAdditionalPropertiesClass) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Uuid) {
+	if !IsNil(o.Uuid) {
 		toSerialize["uuid"] = o.Uuid
 	}
-	if !isNil(o.DateTime) {
+	if !IsNil(o.DateTime) {
 		toSerialize["dateTime"] = o.DateTime
 	}
-	if !isNil(o.Map) {
+	if !IsNil(o.Map) {
 		toSerialize["map"] = o.Map
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_name.go b/samples/openapi3/client/petstore/go/go-petstore/model_name.go
index cdec0e50403..934e03ff549 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_name.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_name.go
@@ -72,7 +72,7 @@ func (o *Name) SetName(v int32) {
 
 // GetSnakeCase returns the SnakeCase field value if set, zero value otherwise.
 func (o *Name) GetSnakeCase() int32 {
-	if o == nil || isNil(o.SnakeCase) {
+	if o == nil || IsNil(o.SnakeCase) {
 		var ret int32
 		return ret
 	}
@@ -82,7 +82,7 @@ func (o *Name) GetSnakeCase() int32 {
 // GetSnakeCaseOk returns a tuple with the SnakeCase field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Name) GetSnakeCaseOk() (*int32, bool) {
-	if o == nil || isNil(o.SnakeCase) {
+	if o == nil || IsNil(o.SnakeCase) {
 		return nil, false
 	}
 	return o.SnakeCase, true
@@ -90,7 +90,7 @@ func (o *Name) GetSnakeCaseOk() (*int32, bool) {
 
 // HasSnakeCase returns a boolean if a field has been set.
 func (o *Name) HasSnakeCase() bool {
-	if o != nil && !isNil(o.SnakeCase) {
+	if o != nil && !IsNil(o.SnakeCase) {
 		return true
 	}
 
@@ -104,7 +104,7 @@ func (o *Name) SetSnakeCase(v int32) {
 
 // GetProperty returns the Property field value if set, zero value otherwise.
 func (o *Name) GetProperty() string {
-	if o == nil || isNil(o.Property) {
+	if o == nil || IsNil(o.Property) {
 		var ret string
 		return ret
 	}
@@ -114,7 +114,7 @@ func (o *Name) GetProperty() string {
 // GetPropertyOk returns a tuple with the Property field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Name) GetPropertyOk() (*string, bool) {
-	if o == nil || isNil(o.Property) {
+	if o == nil || IsNil(o.Property) {
 		return nil, false
 	}
 	return o.Property, true
@@ -122,7 +122,7 @@ func (o *Name) GetPropertyOk() (*string, bool) {
 
 // HasProperty returns a boolean if a field has been set.
 func (o *Name) HasProperty() bool {
-	if o != nil && !isNil(o.Property) {
+	if o != nil && !IsNil(o.Property) {
 		return true
 	}
 
@@ -136,7 +136,7 @@ func (o *Name) SetProperty(v string) {
 
 // GetVar123Number returns the Var123Number field value if set, zero value otherwise.
 func (o *Name) GetVar123Number() int32 {
-	if o == nil || isNil(o.Var123Number) {
+	if o == nil || IsNil(o.Var123Number) {
 		var ret int32
 		return ret
 	}
@@ -146,7 +146,7 @@ func (o *Name) GetVar123Number() int32 {
 // GetVar123NumberOk returns a tuple with the Var123Number field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Name) GetVar123NumberOk() (*int32, bool) {
-	if o == nil || isNil(o.Var123Number) {
+	if o == nil || IsNil(o.Var123Number) {
 		return nil, false
 	}
 	return o.Var123Number, true
@@ -154,7 +154,7 @@ func (o *Name) GetVar123NumberOk() (*int32, bool) {
 
 // HasVar123Number returns a boolean if a field has been set.
 func (o *Name) HasVar123Number() bool {
-	if o != nil && !isNil(o.Var123Number) {
+	if o != nil && !IsNil(o.Var123Number) {
 		return true
 	}
 
@@ -178,7 +178,7 @@ func (o Name) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
 	toSerialize["name"] = o.Name
 	// skip: snake_case is readOnly
-	if !isNil(o.Property) {
+	if !IsNil(o.Property) {
 		toSerialize["property"] = o.Property
 	}
 	// skip: 123Number is readOnly
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_nullable_all_of.go b/samples/openapi3/client/petstore/go/go-petstore/model_nullable_all_of.go
index b773106a35e..f9f10c7e5ff 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_nullable_all_of.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_nullable_all_of.go
@@ -44,7 +44,7 @@ func NewNullableAllOfWithDefaults() *NullableAllOf {
 
 // GetChild returns the Child field value if set, zero value otherwise (both if not set or set to explicit null).
 func (o *NullableAllOf) GetChild() NullableAllOfChild {
-	if o == nil || isNil(o.Child.Get()) {
+	if o == nil || IsNil(o.Child.Get()) {
 		var ret NullableAllOfChild
 		return ret
 	}
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_nullable_all_of_child.go b/samples/openapi3/client/petstore/go/go-petstore/model_nullable_all_of_child.go
index 777c1cba476..7b28b820f33 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_nullable_all_of_child.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_nullable_all_of_child.go
@@ -44,7 +44,7 @@ func NewNullableAllOfChildWithDefaults() *NullableAllOfChild {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *NullableAllOfChild) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *NullableAllOfChild) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *NullableAllOfChild) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -62,7 +62,7 @@ func (o *NullableAllOfChild) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *NullableAllOfChild) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o NullableAllOfChild) MarshalJSON() ([]byte, error) {
 
 func (o NullableAllOfChild) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_nullable_class.go b/samples/openapi3/client/petstore/go/go-petstore/model_nullable_class.go
index 3f55258256f..0c173346d22 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_nullable_class.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_nullable_class.go
@@ -57,7 +57,7 @@ func NewNullableClassWithDefaults() *NullableClass {
 
 // GetIntegerProp returns the IntegerProp field value if set, zero value otherwise (both if not set or set to explicit null).
 func (o *NullableClass) GetIntegerProp() int32 {
-	if o == nil || isNil(o.IntegerProp.Get()) {
+	if o == nil || IsNil(o.IntegerProp.Get()) {
 		var ret int32
 		return ret
 	}
@@ -99,7 +99,7 @@ func (o *NullableClass) UnsetIntegerProp() {
 
 // GetNumberProp returns the NumberProp field value if set, zero value otherwise (both if not set or set to explicit null).
 func (o *NullableClass) GetNumberProp() float32 {
-	if o == nil || isNil(o.NumberProp.Get()) {
+	if o == nil || IsNil(o.NumberProp.Get()) {
 		var ret float32
 		return ret
 	}
@@ -141,7 +141,7 @@ func (o *NullableClass) UnsetNumberProp() {
 
 // GetBooleanProp returns the BooleanProp field value if set, zero value otherwise (both if not set or set to explicit null).
 func (o *NullableClass) GetBooleanProp() bool {
-	if o == nil || isNil(o.BooleanProp.Get()) {
+	if o == nil || IsNil(o.BooleanProp.Get()) {
 		var ret bool
 		return ret
 	}
@@ -183,7 +183,7 @@ func (o *NullableClass) UnsetBooleanProp() {
 
 // GetStringProp returns the StringProp field value if set, zero value otherwise (both if not set or set to explicit null).
 func (o *NullableClass) GetStringProp() string {
-	if o == nil || isNil(o.StringProp.Get()) {
+	if o == nil || IsNil(o.StringProp.Get()) {
 		var ret string
 		return ret
 	}
@@ -225,7 +225,7 @@ func (o *NullableClass) UnsetStringProp() {
 
 // GetDateProp returns the DateProp field value if set, zero value otherwise (both if not set or set to explicit null).
 func (o *NullableClass) GetDateProp() string {
-	if o == nil || isNil(o.DateProp.Get()) {
+	if o == nil || IsNil(o.DateProp.Get()) {
 		var ret string
 		return ret
 	}
@@ -267,7 +267,7 @@ func (o *NullableClass) UnsetDateProp() {
 
 // GetDatetimeProp returns the DatetimeProp field value if set, zero value otherwise (both if not set or set to explicit null).
 func (o *NullableClass) GetDatetimeProp() time.Time {
-	if o == nil || isNil(o.DatetimeProp.Get()) {
+	if o == nil || IsNil(o.DatetimeProp.Get()) {
 		var ret time.Time
 		return ret
 	}
@@ -320,7 +320,7 @@ func (o *NullableClass) GetArrayNullableProp() []map[string]interface{} {
 // and a boolean to check if the value has been set.
 // NOTE: If the value is an explicit nil, `nil, true` will be returned
 func (o *NullableClass) GetArrayNullablePropOk() ([]map[string]interface{}, bool) {
-	if o == nil || isNil(o.ArrayNullableProp) {
+	if o == nil || IsNil(o.ArrayNullableProp) {
 		return nil, false
 	}
 	return o.ArrayNullableProp, true
@@ -328,7 +328,7 @@ func (o *NullableClass) GetArrayNullablePropOk() ([]map[string]interface{}, bool
 
 // HasArrayNullableProp returns a boolean if a field has been set.
 func (o *NullableClass) HasArrayNullableProp() bool {
-	if o != nil && isNil(o.ArrayNullableProp) {
+	if o != nil && IsNil(o.ArrayNullableProp) {
 		return true
 	}
 
@@ -353,7 +353,7 @@ func (o *NullableClass) GetArrayAndItemsNullableProp() []*map[string]interface{}
 // and a boolean to check if the value has been set.
 // NOTE: If the value is an explicit nil, `nil, true` will be returned
 func (o *NullableClass) GetArrayAndItemsNullablePropOk() ([]*map[string]interface{}, bool) {
-	if o == nil || isNil(o.ArrayAndItemsNullableProp) {
+	if o == nil || IsNil(o.ArrayAndItemsNullableProp) {
 		return nil, false
 	}
 	return o.ArrayAndItemsNullableProp, true
@@ -361,7 +361,7 @@ func (o *NullableClass) GetArrayAndItemsNullablePropOk() ([]*map[string]interfac
 
 // HasArrayAndItemsNullableProp returns a boolean if a field has been set.
 func (o *NullableClass) HasArrayAndItemsNullableProp() bool {
-	if o != nil && isNil(o.ArrayAndItemsNullableProp) {
+	if o != nil && IsNil(o.ArrayAndItemsNullableProp) {
 		return true
 	}
 
@@ -375,7 +375,7 @@ func (o *NullableClass) SetArrayAndItemsNullableProp(v []*map[string]interface{}
 
 // GetArrayItemsNullable returns the ArrayItemsNullable field value if set, zero value otherwise.
 func (o *NullableClass) GetArrayItemsNullable() []*map[string]interface{} {
-	if o == nil || isNil(o.ArrayItemsNullable) {
+	if o == nil || IsNil(o.ArrayItemsNullable) {
 		var ret []*map[string]interface{}
 		return ret
 	}
@@ -385,7 +385,7 @@ func (o *NullableClass) GetArrayItemsNullable() []*map[string]interface{} {
 // GetArrayItemsNullableOk returns a tuple with the ArrayItemsNullable field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *NullableClass) GetArrayItemsNullableOk() ([]*map[string]interface{}, bool) {
-	if o == nil || isNil(o.ArrayItemsNullable) {
+	if o == nil || IsNil(o.ArrayItemsNullable) {
 		return nil, false
 	}
 	return o.ArrayItemsNullable, true
@@ -393,7 +393,7 @@ func (o *NullableClass) GetArrayItemsNullableOk() ([]*map[string]interface{}, bo
 
 // HasArrayItemsNullable returns a boolean if a field has been set.
 func (o *NullableClass) HasArrayItemsNullable() bool {
-	if o != nil && !isNil(o.ArrayItemsNullable) {
+	if o != nil && !IsNil(o.ArrayItemsNullable) {
 		return true
 	}
 
@@ -418,7 +418,7 @@ func (o *NullableClass) GetObjectNullableProp() map[string]map[string]interface{
 // and a boolean to check if the value has been set.
 // NOTE: If the value is an explicit nil, `nil, true` will be returned
 func (o *NullableClass) GetObjectNullablePropOk() (map[string]map[string]interface{}, bool) {
-	if o == nil || isNil(o.ObjectNullableProp) {
+	if o == nil || IsNil(o.ObjectNullableProp) {
 		return map[string]map[string]interface{}{}, false
 	}
 	return o.ObjectNullableProp, true
@@ -426,7 +426,7 @@ func (o *NullableClass) GetObjectNullablePropOk() (map[string]map[string]interfa
 
 // HasObjectNullableProp returns a boolean if a field has been set.
 func (o *NullableClass) HasObjectNullableProp() bool {
-	if o != nil && isNil(o.ObjectNullableProp) {
+	if o != nil && IsNil(o.ObjectNullableProp) {
 		return true
 	}
 
@@ -451,7 +451,7 @@ func (o *NullableClass) GetObjectAndItemsNullableProp() map[string]map[string]in
 // and a boolean to check if the value has been set.
 // NOTE: If the value is an explicit nil, `nil, true` will be returned
 func (o *NullableClass) GetObjectAndItemsNullablePropOk() (map[string]map[string]interface{}, bool) {
-	if o == nil || isNil(o.ObjectAndItemsNullableProp) {
+	if o == nil || IsNil(o.ObjectAndItemsNullableProp) {
 		return map[string]map[string]interface{}{}, false
 	}
 	return o.ObjectAndItemsNullableProp, true
@@ -459,7 +459,7 @@ func (o *NullableClass) GetObjectAndItemsNullablePropOk() (map[string]map[string
 
 // HasObjectAndItemsNullableProp returns a boolean if a field has been set.
 func (o *NullableClass) HasObjectAndItemsNullableProp() bool {
-	if o != nil && isNil(o.ObjectAndItemsNullableProp) {
+	if o != nil && IsNil(o.ObjectAndItemsNullableProp) {
 		return true
 	}
 
@@ -473,7 +473,7 @@ func (o *NullableClass) SetObjectAndItemsNullableProp(v map[string]map[string]in
 
 // GetObjectItemsNullable returns the ObjectItemsNullable field value if set, zero value otherwise.
 func (o *NullableClass) GetObjectItemsNullable() map[string]map[string]interface{} {
-	if o == nil || isNil(o.ObjectItemsNullable) {
+	if o == nil || IsNil(o.ObjectItemsNullable) {
 		var ret map[string]map[string]interface{}
 		return ret
 	}
@@ -483,7 +483,7 @@ func (o *NullableClass) GetObjectItemsNullable() map[string]map[string]interface
 // GetObjectItemsNullableOk returns a tuple with the ObjectItemsNullable field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *NullableClass) GetObjectItemsNullableOk() (map[string]map[string]interface{}, bool) {
-	if o == nil || isNil(o.ObjectItemsNullable) {
+	if o == nil || IsNil(o.ObjectItemsNullable) {
 		return map[string]map[string]interface{}{}, false
 	}
 	return o.ObjectItemsNullable, true
@@ -491,7 +491,7 @@ func (o *NullableClass) GetObjectItemsNullableOk() (map[string]map[string]interf
 
 // HasObjectItemsNullable returns a boolean if a field has been set.
 func (o *NullableClass) HasObjectItemsNullable() bool {
-	if o != nil && !isNil(o.ObjectItemsNullable) {
+	if o != nil && !IsNil(o.ObjectItemsNullable) {
 		return true
 	}
 
@@ -537,7 +537,7 @@ func (o NullableClass) ToMap() (map[string]interface{}, error) {
 	if o.ArrayAndItemsNullableProp != nil {
 		toSerialize["array_and_items_nullable_prop"] = o.ArrayAndItemsNullableProp
 	}
-	if !isNil(o.ArrayItemsNullable) {
+	if !IsNil(o.ArrayItemsNullable) {
 		toSerialize["array_items_nullable"] = o.ArrayItemsNullable
 	}
 	if o.ObjectNullableProp != nil {
@@ -546,7 +546,7 @@ func (o NullableClass) ToMap() (map[string]interface{}, error) {
 	if o.ObjectAndItemsNullableProp != nil {
 		toSerialize["object_and_items_nullable_prop"] = o.ObjectAndItemsNullableProp
 	}
-	if !isNil(o.ObjectItemsNullable) {
+	if !IsNil(o.ObjectItemsNullable) {
 		toSerialize["object_items_nullable"] = o.ObjectItemsNullable
 	}
 	return toSerialize, nil
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_number_only.go b/samples/openapi3/client/petstore/go/go-petstore/model_number_only.go
index 7b98f85d8b7..36bd0c4b7a2 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_number_only.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_number_only.go
@@ -44,7 +44,7 @@ func NewNumberOnlyWithDefaults() *NumberOnly {
 
 // GetJustNumber returns the JustNumber field value if set, zero value otherwise.
 func (o *NumberOnly) GetJustNumber() float32 {
-	if o == nil || isNil(o.JustNumber) {
+	if o == nil || IsNil(o.JustNumber) {
 		var ret float32
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *NumberOnly) GetJustNumber() float32 {
 // GetJustNumberOk returns a tuple with the JustNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *NumberOnly) GetJustNumberOk() (*float32, bool) {
-	if o == nil || isNil(o.JustNumber) {
+	if o == nil || IsNil(o.JustNumber) {
 		return nil, false
 	}
 	return o.JustNumber, true
@@ -62,7 +62,7 @@ func (o *NumberOnly) GetJustNumberOk() (*float32, bool) {
 
 // HasJustNumber returns a boolean if a field has been set.
 func (o *NumberOnly) HasJustNumber() bool {
-	if o != nil && !isNil(o.JustNumber) {
+	if o != nil && !IsNil(o.JustNumber) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o NumberOnly) MarshalJSON() ([]byte, error) {
 
 func (o NumberOnly) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.JustNumber) {
+	if !IsNil(o.JustNumber) {
 		toSerialize["JustNumber"] = o.JustNumber
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_one_of_primitive_type_child.go b/samples/openapi3/client/petstore/go/go-petstore/model_one_of_primitive_type_child.go
index f52fa72517f..1c719015646 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_one_of_primitive_type_child.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_one_of_primitive_type_child.go
@@ -44,7 +44,7 @@ func NewOneOfPrimitiveTypeChildWithDefaults() *OneOfPrimitiveTypeChild {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *OneOfPrimitiveTypeChild) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *OneOfPrimitiveTypeChild) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *OneOfPrimitiveTypeChild) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -62,7 +62,7 @@ func (o *OneOfPrimitiveTypeChild) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *OneOfPrimitiveTypeChild) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o OneOfPrimitiveTypeChild) MarshalJSON() ([]byte, error) {
 
 func (o OneOfPrimitiveTypeChild) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_order.go b/samples/openapi3/client/petstore/go/go-petstore/model_order.go
index 45af84e4070..a4be8a04ee2 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_order.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_order.go
@@ -55,7 +55,7 @@ func NewOrderWithDefaults() *Order {
 
 // GetId returns the Id field value if set, zero value otherwise.
 func (o *Order) GetId() int64 {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		var ret int64
 		return ret
 	}
@@ -65,7 +65,7 @@ func (o *Order) GetId() int64 {
 // GetIdOk returns a tuple with the Id field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		return nil, false
 	}
 	return o.Id, true
@@ -73,7 +73,7 @@ func (o *Order) GetIdOk() (*int64, bool) {
 
 // HasId returns a boolean if a field has been set.
 func (o *Order) HasId() bool {
-	if o != nil && !isNil(o.Id) {
+	if o != nil && !IsNil(o.Id) {
 		return true
 	}
 
@@ -87,7 +87,7 @@ func (o *Order) SetId(v int64) {
 
 // GetPetId returns the PetId field value if set, zero value otherwise.
 func (o *Order) GetPetId() int64 {
-	if o == nil || isNil(o.PetId) {
+	if o == nil || IsNil(o.PetId) {
 		var ret int64
 		return ret
 	}
@@ -97,7 +97,7 @@ func (o *Order) GetPetId() int64 {
 // GetPetIdOk returns a tuple with the PetId field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetPetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.PetId) {
+	if o == nil || IsNil(o.PetId) {
 		return nil, false
 	}
 	return o.PetId, true
@@ -105,7 +105,7 @@ func (o *Order) GetPetIdOk() (*int64, bool) {
 
 // HasPetId returns a boolean if a field has been set.
 func (o *Order) HasPetId() bool {
-	if o != nil && !isNil(o.PetId) {
+	if o != nil && !IsNil(o.PetId) {
 		return true
 	}
 
@@ -119,7 +119,7 @@ func (o *Order) SetPetId(v int64) {
 
 // GetQuantity returns the Quantity field value if set, zero value otherwise.
 func (o *Order) GetQuantity() int32 {
-	if o == nil || isNil(o.Quantity) {
+	if o == nil || IsNil(o.Quantity) {
 		var ret int32
 		return ret
 	}
@@ -129,7 +129,7 @@ func (o *Order) GetQuantity() int32 {
 // GetQuantityOk returns a tuple with the Quantity field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetQuantityOk() (*int32, bool) {
-	if o == nil || isNil(o.Quantity) {
+	if o == nil || IsNil(o.Quantity) {
 		return nil, false
 	}
 	return o.Quantity, true
@@ -137,7 +137,7 @@ func (o *Order) GetQuantityOk() (*int32, bool) {
 
 // HasQuantity returns a boolean if a field has been set.
 func (o *Order) HasQuantity() bool {
-	if o != nil && !isNil(o.Quantity) {
+	if o != nil && !IsNil(o.Quantity) {
 		return true
 	}
 
@@ -151,7 +151,7 @@ func (o *Order) SetQuantity(v int32) {
 
 // GetShipDate returns the ShipDate field value if set, zero value otherwise.
 func (o *Order) GetShipDate() time.Time {
-	if o == nil || isNil(o.ShipDate) {
+	if o == nil || IsNil(o.ShipDate) {
 		var ret time.Time
 		return ret
 	}
@@ -161,7 +161,7 @@ func (o *Order) GetShipDate() time.Time {
 // GetShipDateOk returns a tuple with the ShipDate field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetShipDateOk() (*time.Time, bool) {
-	if o == nil || isNil(o.ShipDate) {
+	if o == nil || IsNil(o.ShipDate) {
 		return nil, false
 	}
 	return o.ShipDate, true
@@ -169,7 +169,7 @@ func (o *Order) GetShipDateOk() (*time.Time, bool) {
 
 // HasShipDate returns a boolean if a field has been set.
 func (o *Order) HasShipDate() bool {
-	if o != nil && !isNil(o.ShipDate) {
+	if o != nil && !IsNil(o.ShipDate) {
 		return true
 	}
 
@@ -183,7 +183,7 @@ func (o *Order) SetShipDate(v time.Time) {
 
 // GetStatus returns the Status field value if set, zero value otherwise.
 func (o *Order) GetStatus() string {
-	if o == nil || isNil(o.Status) {
+	if o == nil || IsNil(o.Status) {
 		var ret string
 		return ret
 	}
@@ -193,7 +193,7 @@ func (o *Order) GetStatus() string {
 // GetStatusOk returns a tuple with the Status field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetStatusOk() (*string, bool) {
-	if o == nil || isNil(o.Status) {
+	if o == nil || IsNil(o.Status) {
 		return nil, false
 	}
 	return o.Status, true
@@ -201,7 +201,7 @@ func (o *Order) GetStatusOk() (*string, bool) {
 
 // HasStatus returns a boolean if a field has been set.
 func (o *Order) HasStatus() bool {
-	if o != nil && !isNil(o.Status) {
+	if o != nil && !IsNil(o.Status) {
 		return true
 	}
 
@@ -215,7 +215,7 @@ func (o *Order) SetStatus(v string) {
 
 // GetComplete returns the Complete field value if set, zero value otherwise.
 func (o *Order) GetComplete() bool {
-	if o == nil || isNil(o.Complete) {
+	if o == nil || IsNil(o.Complete) {
 		var ret bool
 		return ret
 	}
@@ -225,7 +225,7 @@ func (o *Order) GetComplete() bool {
 // GetCompleteOk returns a tuple with the Complete field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Order) GetCompleteOk() (*bool, bool) {
-	if o == nil || isNil(o.Complete) {
+	if o == nil || IsNil(o.Complete) {
 		return nil, false
 	}
 	return o.Complete, true
@@ -233,7 +233,7 @@ func (o *Order) GetCompleteOk() (*bool, bool) {
 
 // HasComplete returns a boolean if a field has been set.
 func (o *Order) HasComplete() bool {
-	if o != nil && !isNil(o.Complete) {
+	if o != nil && !IsNil(o.Complete) {
 		return true
 	}
 
@@ -255,22 +255,22 @@ func (o Order) MarshalJSON() ([]byte, error) {
 
 func (o Order) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Id) {
+	if !IsNil(o.Id) {
 		toSerialize["id"] = o.Id
 	}
-	if !isNil(o.PetId) {
+	if !IsNil(o.PetId) {
 		toSerialize["petId"] = o.PetId
 	}
-	if !isNil(o.Quantity) {
+	if !IsNil(o.Quantity) {
 		toSerialize["quantity"] = o.Quantity
 	}
-	if !isNil(o.ShipDate) {
+	if !IsNil(o.ShipDate) {
 		toSerialize["shipDate"] = o.ShipDate
 	}
-	if !isNil(o.Status) {
+	if !IsNil(o.Status) {
 		toSerialize["status"] = o.Status
 	}
-	if !isNil(o.Complete) {
+	if !IsNil(o.Complete) {
 		toSerialize["complete"] = o.Complete
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_outer_composite.go b/samples/openapi3/client/petstore/go/go-petstore/model_outer_composite.go
index 210cacc2710..74c5518557b 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_outer_composite.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_outer_composite.go
@@ -46,7 +46,7 @@ func NewOuterCompositeWithDefaults() *OuterComposite {
 
 // GetMyNumber returns the MyNumber field value if set, zero value otherwise.
 func (o *OuterComposite) GetMyNumber() float32 {
-	if o == nil || isNil(o.MyNumber) {
+	if o == nil || IsNil(o.MyNumber) {
 		var ret float32
 		return ret
 	}
@@ -56,7 +56,7 @@ func (o *OuterComposite) GetMyNumber() float32 {
 // GetMyNumberOk returns a tuple with the MyNumber field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *OuterComposite) GetMyNumberOk() (*float32, bool) {
-	if o == nil || isNil(o.MyNumber) {
+	if o == nil || IsNil(o.MyNumber) {
 		return nil, false
 	}
 	return o.MyNumber, true
@@ -64,7 +64,7 @@ func (o *OuterComposite) GetMyNumberOk() (*float32, bool) {
 
 // HasMyNumber returns a boolean if a field has been set.
 func (o *OuterComposite) HasMyNumber() bool {
-	if o != nil && !isNil(o.MyNumber) {
+	if o != nil && !IsNil(o.MyNumber) {
 		return true
 	}
 
@@ -78,7 +78,7 @@ func (o *OuterComposite) SetMyNumber(v float32) {
 
 // GetMyString returns the MyString field value if set, zero value otherwise.
 func (o *OuterComposite) GetMyString() string {
-	if o == nil || isNil(o.MyString) {
+	if o == nil || IsNil(o.MyString) {
 		var ret string
 		return ret
 	}
@@ -88,7 +88,7 @@ func (o *OuterComposite) GetMyString() string {
 // GetMyStringOk returns a tuple with the MyString field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *OuterComposite) GetMyStringOk() (*string, bool) {
-	if o == nil || isNil(o.MyString) {
+	if o == nil || IsNil(o.MyString) {
 		return nil, false
 	}
 	return o.MyString, true
@@ -96,7 +96,7 @@ func (o *OuterComposite) GetMyStringOk() (*string, bool) {
 
 // HasMyString returns a boolean if a field has been set.
 func (o *OuterComposite) HasMyString() bool {
-	if o != nil && !isNil(o.MyString) {
+	if o != nil && !IsNil(o.MyString) {
 		return true
 	}
 
@@ -110,7 +110,7 @@ func (o *OuterComposite) SetMyString(v string) {
 
 // GetMyBoolean returns the MyBoolean field value if set, zero value otherwise.
 func (o *OuterComposite) GetMyBoolean() bool {
-	if o == nil || isNil(o.MyBoolean) {
+	if o == nil || IsNil(o.MyBoolean) {
 		var ret bool
 		return ret
 	}
@@ -120,7 +120,7 @@ func (o *OuterComposite) GetMyBoolean() bool {
 // GetMyBooleanOk returns a tuple with the MyBoolean field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *OuterComposite) GetMyBooleanOk() (*bool, bool) {
-	if o == nil || isNil(o.MyBoolean) {
+	if o == nil || IsNil(o.MyBoolean) {
 		return nil, false
 	}
 	return o.MyBoolean, true
@@ -128,7 +128,7 @@ func (o *OuterComposite) GetMyBooleanOk() (*bool, bool) {
 
 // HasMyBoolean returns a boolean if a field has been set.
 func (o *OuterComposite) HasMyBoolean() bool {
-	if o != nil && !isNil(o.MyBoolean) {
+	if o != nil && !IsNil(o.MyBoolean) {
 		return true
 	}
 
@@ -150,13 +150,13 @@ func (o OuterComposite) MarshalJSON() ([]byte, error) {
 
 func (o OuterComposite) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.MyNumber) {
+	if !IsNil(o.MyNumber) {
 		toSerialize["my_number"] = o.MyNumber
 	}
-	if !isNil(o.MyString) {
+	if !IsNil(o.MyString) {
 		toSerialize["my_string"] = o.MyString
 	}
-	if !isNil(o.MyBoolean) {
+	if !IsNil(o.MyBoolean) {
 		toSerialize["my_boolean"] = o.MyBoolean
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_pet.go b/samples/openapi3/client/petstore/go/go-petstore/model_pet.go
index 008200fcb55..156f6be2f76 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_pet.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_pet.go
@@ -53,7 +53,7 @@ func NewPetWithDefaults() *Pet {
 
 // GetId returns the Id field value if set, zero value otherwise.
 func (o *Pet) GetId() int64 {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		var ret int64
 		return ret
 	}
@@ -63,7 +63,7 @@ func (o *Pet) GetId() int64 {
 // GetIdOk returns a tuple with the Id field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Pet) GetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		return nil, false
 	}
 	return o.Id, true
@@ -71,7 +71,7 @@ func (o *Pet) GetIdOk() (*int64, bool) {
 
 // HasId returns a boolean if a field has been set.
 func (o *Pet) HasId() bool {
-	if o != nil && !isNil(o.Id) {
+	if o != nil && !IsNil(o.Id) {
 		return true
 	}
 
@@ -85,7 +85,7 @@ func (o *Pet) SetId(v int64) {
 
 // GetCategory returns the Category field value if set, zero value otherwise.
 func (o *Pet) GetCategory() Category {
-	if o == nil || isNil(o.Category) {
+	if o == nil || IsNil(o.Category) {
 		var ret Category
 		return ret
 	}
@@ -95,7 +95,7 @@ func (o *Pet) GetCategory() Category {
 // GetCategoryOk returns a tuple with the Category field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Pet) GetCategoryOk() (*Category, bool) {
-	if o == nil || isNil(o.Category) {
+	if o == nil || IsNil(o.Category) {
 		return nil, false
 	}
 	return o.Category, true
@@ -103,7 +103,7 @@ func (o *Pet) GetCategoryOk() (*Category, bool) {
 
 // HasCategory returns a boolean if a field has been set.
 func (o *Pet) HasCategory() bool {
-	if o != nil && !isNil(o.Category) {
+	if o != nil && !IsNil(o.Category) {
 		return true
 	}
 
@@ -165,7 +165,7 @@ func (o *Pet) SetPhotoUrls(v []string) {
 
 // GetTags returns the Tags field value if set, zero value otherwise.
 func (o *Pet) GetTags() []Tag {
-	if o == nil || isNil(o.Tags) {
+	if o == nil || IsNil(o.Tags) {
 		var ret []Tag
 		return ret
 	}
@@ -175,7 +175,7 @@ func (o *Pet) GetTags() []Tag {
 // GetTagsOk returns a tuple with the Tags field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Pet) GetTagsOk() ([]Tag, bool) {
-	if o == nil || isNil(o.Tags) {
+	if o == nil || IsNil(o.Tags) {
 		return nil, false
 	}
 	return o.Tags, true
@@ -183,7 +183,7 @@ func (o *Pet) GetTagsOk() ([]Tag, bool) {
 
 // HasTags returns a boolean if a field has been set.
 func (o *Pet) HasTags() bool {
-	if o != nil && !isNil(o.Tags) {
+	if o != nil && !IsNil(o.Tags) {
 		return true
 	}
 
@@ -198,7 +198,7 @@ func (o *Pet) SetTags(v []Tag) {
 // GetStatus returns the Status field value if set, zero value otherwise.
 // Deprecated
 func (o *Pet) GetStatus() string {
-	if o == nil || isNil(o.Status) {
+	if o == nil || IsNil(o.Status) {
 		var ret string
 		return ret
 	}
@@ -209,7 +209,7 @@ func (o *Pet) GetStatus() string {
 // and a boolean to check if the value has been set.
 // Deprecated
 func (o *Pet) GetStatusOk() (*string, bool) {
-	if o == nil || isNil(o.Status) {
+	if o == nil || IsNil(o.Status) {
 		return nil, false
 	}
 	return o.Status, true
@@ -217,7 +217,7 @@ func (o *Pet) GetStatusOk() (*string, bool) {
 
 // HasStatus returns a boolean if a field has been set.
 func (o *Pet) HasStatus() bool {
-	if o != nil && !isNil(o.Status) {
+	if o != nil && !IsNil(o.Status) {
 		return true
 	}
 
@@ -240,18 +240,18 @@ func (o Pet) MarshalJSON() ([]byte, error) {
 
 func (o Pet) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Id) {
+	if !IsNil(o.Id) {
 		toSerialize["id"] = o.Id
 	}
-	if !isNil(o.Category) {
+	if !IsNil(o.Category) {
 		toSerialize["category"] = o.Category
 	}
 	toSerialize["name"] = o.Name
 	toSerialize["photoUrls"] = o.PhotoUrls
-	if !isNil(o.Tags) {
+	if !IsNil(o.Tags) {
 		toSerialize["tags"] = o.Tags
 	}
-	if !isNil(o.Status) {
+	if !IsNil(o.Status) {
 		toSerialize["status"] = o.Status
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_read_only_first.go b/samples/openapi3/client/petstore/go/go-petstore/model_read_only_first.go
index 93fc4b5a29f..0b0334c30f3 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_read_only_first.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_read_only_first.go
@@ -45,7 +45,7 @@ func NewReadOnlyFirstWithDefaults() *ReadOnlyFirst {
 
 // GetBar returns the Bar field value if set, zero value otherwise.
 func (o *ReadOnlyFirst) GetBar() string {
-	if o == nil || isNil(o.Bar) {
+	if o == nil || IsNil(o.Bar) {
 		var ret string
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *ReadOnlyFirst) GetBar() string {
 // GetBarOk returns a tuple with the Bar field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyFirst) GetBarOk() (*string, bool) {
-	if o == nil || isNil(o.Bar) {
+	if o == nil || IsNil(o.Bar) {
 		return nil, false
 	}
 	return o.Bar, true
@@ -63,7 +63,7 @@ func (o *ReadOnlyFirst) GetBarOk() (*string, bool) {
 
 // HasBar returns a boolean if a field has been set.
 func (o *ReadOnlyFirst) HasBar() bool {
-	if o != nil && !isNil(o.Bar) {
+	if o != nil && !IsNil(o.Bar) {
 		return true
 	}
 
@@ -77,7 +77,7 @@ func (o *ReadOnlyFirst) SetBar(v string) {
 
 // GetBaz returns the Baz field value if set, zero value otherwise.
 func (o *ReadOnlyFirst) GetBaz() string {
-	if o == nil || isNil(o.Baz) {
+	if o == nil || IsNil(o.Baz) {
 		var ret string
 		return ret
 	}
@@ -87,7 +87,7 @@ func (o *ReadOnlyFirst) GetBaz() string {
 // GetBazOk returns a tuple with the Baz field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyFirst) GetBazOk() (*string, bool) {
-	if o == nil || isNil(o.Baz) {
+	if o == nil || IsNil(o.Baz) {
 		return nil, false
 	}
 	return o.Baz, true
@@ -95,7 +95,7 @@ func (o *ReadOnlyFirst) GetBazOk() (*string, bool) {
 
 // HasBaz returns a boolean if a field has been set.
 func (o *ReadOnlyFirst) HasBaz() bool {
-	if o != nil && !isNil(o.Baz) {
+	if o != nil && !IsNil(o.Baz) {
 		return true
 	}
 
@@ -118,7 +118,7 @@ func (o ReadOnlyFirst) MarshalJSON() ([]byte, error) {
 func (o ReadOnlyFirst) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
 	// skip: bar is readOnly
-	if !isNil(o.Baz) {
+	if !IsNil(o.Baz) {
 		toSerialize["baz"] = o.Baz
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_read_only_with_default.go b/samples/openapi3/client/petstore/go/go-petstore/model_read_only_with_default.go
index 9e692e9280e..90522780d32 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_read_only_with_default.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_read_only_with_default.go
@@ -62,7 +62,7 @@ func NewReadOnlyWithDefaultWithDefaults() *ReadOnlyWithDefault {
 
 // GetProp1 returns the Prop1 field value if set, zero value otherwise.
 func (o *ReadOnlyWithDefault) GetProp1() string {
-	if o == nil || isNil(o.Prop1) {
+	if o == nil || IsNil(o.Prop1) {
 		var ret string
 		return ret
 	}
@@ -72,7 +72,7 @@ func (o *ReadOnlyWithDefault) GetProp1() string {
 // GetProp1Ok returns a tuple with the Prop1 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyWithDefault) GetProp1Ok() (*string, bool) {
-	if o == nil || isNil(o.Prop1) {
+	if o == nil || IsNil(o.Prop1) {
 		return nil, false
 	}
 	return o.Prop1, true
@@ -80,7 +80,7 @@ func (o *ReadOnlyWithDefault) GetProp1Ok() (*string, bool) {
 
 // HasProp1 returns a boolean if a field has been set.
 func (o *ReadOnlyWithDefault) HasProp1() bool {
-	if o != nil && !isNil(o.Prop1) {
+	if o != nil && !IsNil(o.Prop1) {
 		return true
 	}
 
@@ -94,7 +94,7 @@ func (o *ReadOnlyWithDefault) SetProp1(v string) {
 
 // GetProp2 returns the Prop2 field value if set, zero value otherwise.
 func (o *ReadOnlyWithDefault) GetProp2() string {
-	if o == nil || isNil(o.Prop2) {
+	if o == nil || IsNil(o.Prop2) {
 		var ret string
 		return ret
 	}
@@ -104,7 +104,7 @@ func (o *ReadOnlyWithDefault) GetProp2() string {
 // GetProp2Ok returns a tuple with the Prop2 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyWithDefault) GetProp2Ok() (*string, bool) {
-	if o == nil || isNil(o.Prop2) {
+	if o == nil || IsNil(o.Prop2) {
 		return nil, false
 	}
 	return o.Prop2, true
@@ -112,7 +112,7 @@ func (o *ReadOnlyWithDefault) GetProp2Ok() (*string, bool) {
 
 // HasProp2 returns a boolean if a field has been set.
 func (o *ReadOnlyWithDefault) HasProp2() bool {
-	if o != nil && !isNil(o.Prop2) {
+	if o != nil && !IsNil(o.Prop2) {
 		return true
 	}
 
@@ -126,7 +126,7 @@ func (o *ReadOnlyWithDefault) SetProp2(v string) {
 
 // GetProp3 returns the Prop3 field value if set, zero value otherwise.
 func (o *ReadOnlyWithDefault) GetProp3() string {
-	if o == nil || isNil(o.Prop3) {
+	if o == nil || IsNil(o.Prop3) {
 		var ret string
 		return ret
 	}
@@ -136,7 +136,7 @@ func (o *ReadOnlyWithDefault) GetProp3() string {
 // GetProp3Ok returns a tuple with the Prop3 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyWithDefault) GetProp3Ok() (*string, bool) {
-	if o == nil || isNil(o.Prop3) {
+	if o == nil || IsNil(o.Prop3) {
 		return nil, false
 	}
 	return o.Prop3, true
@@ -144,7 +144,7 @@ func (o *ReadOnlyWithDefault) GetProp3Ok() (*string, bool) {
 
 // HasProp3 returns a boolean if a field has been set.
 func (o *ReadOnlyWithDefault) HasProp3() bool {
-	if o != nil && !isNil(o.Prop3) {
+	if o != nil && !IsNil(o.Prop3) {
 		return true
 	}
 
@@ -158,7 +158,7 @@ func (o *ReadOnlyWithDefault) SetProp3(v string) {
 
 // GetBoolProp1 returns the BoolProp1 field value if set, zero value otherwise.
 func (o *ReadOnlyWithDefault) GetBoolProp1() bool {
-	if o == nil || isNil(o.BoolProp1) {
+	if o == nil || IsNil(o.BoolProp1) {
 		var ret bool
 		return ret
 	}
@@ -168,7 +168,7 @@ func (o *ReadOnlyWithDefault) GetBoolProp1() bool {
 // GetBoolProp1Ok returns a tuple with the BoolProp1 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyWithDefault) GetBoolProp1Ok() (*bool, bool) {
-	if o == nil || isNil(o.BoolProp1) {
+	if o == nil || IsNil(o.BoolProp1) {
 		return nil, false
 	}
 	return o.BoolProp1, true
@@ -176,7 +176,7 @@ func (o *ReadOnlyWithDefault) GetBoolProp1Ok() (*bool, bool) {
 
 // HasBoolProp1 returns a boolean if a field has been set.
 func (o *ReadOnlyWithDefault) HasBoolProp1() bool {
-	if o != nil && !isNil(o.BoolProp1) {
+	if o != nil && !IsNil(o.BoolProp1) {
 		return true
 	}
 
@@ -190,7 +190,7 @@ func (o *ReadOnlyWithDefault) SetBoolProp1(v bool) {
 
 // GetBoolProp2 returns the BoolProp2 field value if set, zero value otherwise.
 func (o *ReadOnlyWithDefault) GetBoolProp2() bool {
-	if o == nil || isNil(o.BoolProp2) {
+	if o == nil || IsNil(o.BoolProp2) {
 		var ret bool
 		return ret
 	}
@@ -200,7 +200,7 @@ func (o *ReadOnlyWithDefault) GetBoolProp2() bool {
 // GetBoolProp2Ok returns a tuple with the BoolProp2 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyWithDefault) GetBoolProp2Ok() (*bool, bool) {
-	if o == nil || isNil(o.BoolProp2) {
+	if o == nil || IsNil(o.BoolProp2) {
 		return nil, false
 	}
 	return o.BoolProp2, true
@@ -208,7 +208,7 @@ func (o *ReadOnlyWithDefault) GetBoolProp2Ok() (*bool, bool) {
 
 // HasBoolProp2 returns a boolean if a field has been set.
 func (o *ReadOnlyWithDefault) HasBoolProp2() bool {
-	if o != nil && !isNil(o.BoolProp2) {
+	if o != nil && !IsNil(o.BoolProp2) {
 		return true
 	}
 
@@ -222,7 +222,7 @@ func (o *ReadOnlyWithDefault) SetBoolProp2(v bool) {
 
 // GetIntProp1 returns the IntProp1 field value if set, zero value otherwise.
 func (o *ReadOnlyWithDefault) GetIntProp1() float32 {
-	if o == nil || isNil(o.IntProp1) {
+	if o == nil || IsNil(o.IntProp1) {
 		var ret float32
 		return ret
 	}
@@ -232,7 +232,7 @@ func (o *ReadOnlyWithDefault) GetIntProp1() float32 {
 // GetIntProp1Ok returns a tuple with the IntProp1 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyWithDefault) GetIntProp1Ok() (*float32, bool) {
-	if o == nil || isNil(o.IntProp1) {
+	if o == nil || IsNil(o.IntProp1) {
 		return nil, false
 	}
 	return o.IntProp1, true
@@ -240,7 +240,7 @@ func (o *ReadOnlyWithDefault) GetIntProp1Ok() (*float32, bool) {
 
 // HasIntProp1 returns a boolean if a field has been set.
 func (o *ReadOnlyWithDefault) HasIntProp1() bool {
-	if o != nil && !isNil(o.IntProp1) {
+	if o != nil && !IsNil(o.IntProp1) {
 		return true
 	}
 
@@ -254,7 +254,7 @@ func (o *ReadOnlyWithDefault) SetIntProp1(v float32) {
 
 // GetIntProp2 returns the IntProp2 field value if set, zero value otherwise.
 func (o *ReadOnlyWithDefault) GetIntProp2() float32 {
-	if o == nil || isNil(o.IntProp2) {
+	if o == nil || IsNil(o.IntProp2) {
 		var ret float32
 		return ret
 	}
@@ -264,7 +264,7 @@ func (o *ReadOnlyWithDefault) GetIntProp2() float32 {
 // GetIntProp2Ok returns a tuple with the IntProp2 field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *ReadOnlyWithDefault) GetIntProp2Ok() (*float32, bool) {
-	if o == nil || isNil(o.IntProp2) {
+	if o == nil || IsNil(o.IntProp2) {
 		return nil, false
 	}
 	return o.IntProp2, true
@@ -272,7 +272,7 @@ func (o *ReadOnlyWithDefault) GetIntProp2Ok() (*float32, bool) {
 
 // HasIntProp2 returns a boolean if a field has been set.
 func (o *ReadOnlyWithDefault) HasIntProp2() bool {
-	if o != nil && !isNil(o.IntProp2) {
+	if o != nil && !IsNil(o.IntProp2) {
 		return true
 	}
 
@@ -296,15 +296,15 @@ func (o ReadOnlyWithDefault) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
 	// skip: prop1 is readOnly
 	// skip: prop2 is readOnly
-	if !isNil(o.Prop3) {
+	if !IsNil(o.Prop3) {
 		toSerialize["prop3"] = o.Prop3
 	}
 	// skip: boolProp1 is readOnly
-	if !isNil(o.BoolProp2) {
+	if !IsNil(o.BoolProp2) {
 		toSerialize["boolProp2"] = o.BoolProp2
 	}
 	// skip: intProp1 is readOnly
-	if !isNil(o.IntProp2) {
+	if !IsNil(o.IntProp2) {
 		toSerialize["intProp2"] = o.IntProp2
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_return.go b/samples/openapi3/client/petstore/go/go-petstore/model_return.go
index 77cda0af9e4..e77f7e00792 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_return.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_return.go
@@ -44,7 +44,7 @@ func NewReturnWithDefaults() *Return {
 
 // GetReturn returns the Return field value if set, zero value otherwise.
 func (o *Return) GetReturn() int32 {
-	if o == nil || isNil(o.Return) {
+	if o == nil || IsNil(o.Return) {
 		var ret int32
 		return ret
 	}
@@ -54,7 +54,7 @@ func (o *Return) GetReturn() int32 {
 // GetReturnOk returns a tuple with the Return field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Return) GetReturnOk() (*int32, bool) {
-	if o == nil || isNil(o.Return) {
+	if o == nil || IsNil(o.Return) {
 		return nil, false
 	}
 	return o.Return, true
@@ -62,7 +62,7 @@ func (o *Return) GetReturnOk() (*int32, bool) {
 
 // HasReturn returns a boolean if a field has been set.
 func (o *Return) HasReturn() bool {
-	if o != nil && !isNil(o.Return) {
+	if o != nil && !IsNil(o.Return) {
 		return true
 	}
 
@@ -84,7 +84,7 @@ func (o Return) MarshalJSON() ([]byte, error) {
 
 func (o Return) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Return) {
+	if !IsNil(o.Return) {
 		toSerialize["return"] = o.Return
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_tag.go b/samples/openapi3/client/petstore/go/go-petstore/model_tag.go
index 57fe9198929..f77bf7206b0 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_tag.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_tag.go
@@ -45,7 +45,7 @@ func NewTagWithDefaults() *Tag {
 
 // GetId returns the Id field value if set, zero value otherwise.
 func (o *Tag) GetId() int64 {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		var ret int64
 		return ret
 	}
@@ -55,7 +55,7 @@ func (o *Tag) GetId() int64 {
 // GetIdOk returns a tuple with the Id field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Tag) GetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		return nil, false
 	}
 	return o.Id, true
@@ -63,7 +63,7 @@ func (o *Tag) GetIdOk() (*int64, bool) {
 
 // HasId returns a boolean if a field has been set.
 func (o *Tag) HasId() bool {
-	if o != nil && !isNil(o.Id) {
+	if o != nil && !IsNil(o.Id) {
 		return true
 	}
 
@@ -77,7 +77,7 @@ func (o *Tag) SetId(v int64) {
 
 // GetName returns the Name field value if set, zero value otherwise.
 func (o *Tag) GetName() string {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		var ret string
 		return ret
 	}
@@ -87,7 +87,7 @@ func (o *Tag) GetName() string {
 // GetNameOk returns a tuple with the Name field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Tag) GetNameOk() (*string, bool) {
-	if o == nil || isNil(o.Name) {
+	if o == nil || IsNil(o.Name) {
 		return nil, false
 	}
 	return o.Name, true
@@ -95,7 +95,7 @@ func (o *Tag) GetNameOk() (*string, bool) {
 
 // HasName returns a boolean if a field has been set.
 func (o *Tag) HasName() bool {
-	if o != nil && !isNil(o.Name) {
+	if o != nil && !IsNil(o.Name) {
 		return true
 	}
 
@@ -117,10 +117,10 @@ func (o Tag) MarshalJSON() ([]byte, error) {
 
 func (o Tag) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Id) {
+	if !IsNil(o.Id) {
 		toSerialize["id"] = o.Id
 	}
-	if !isNil(o.Name) {
+	if !IsNil(o.Name) {
 		toSerialize["name"] = o.Name
 	}
 
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_user.go b/samples/openapi3/client/petstore/go/go-petstore/model_user.go
index 389420e8e5c..b884647d1be 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_user.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_user.go
@@ -60,7 +60,7 @@ func NewUserWithDefaults() *User {
 
 // GetId returns the Id field value if set, zero value otherwise.
 func (o *User) GetId() int64 {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		var ret int64
 		return ret
 	}
@@ -70,7 +70,7 @@ func (o *User) GetId() int64 {
 // GetIdOk returns a tuple with the Id field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetIdOk() (*int64, bool) {
-	if o == nil || isNil(o.Id) {
+	if o == nil || IsNil(o.Id) {
 		return nil, false
 	}
 	return o.Id, true
@@ -78,7 +78,7 @@ func (o *User) GetIdOk() (*int64, bool) {
 
 // HasId returns a boolean if a field has been set.
 func (o *User) HasId() bool {
-	if o != nil && !isNil(o.Id) {
+	if o != nil && !IsNil(o.Id) {
 		return true
 	}
 
@@ -92,7 +92,7 @@ func (o *User) SetId(v int64) {
 
 // GetUsername returns the Username field value if set, zero value otherwise.
 func (o *User) GetUsername() string {
-	if o == nil || isNil(o.Username) {
+	if o == nil || IsNil(o.Username) {
 		var ret string
 		return ret
 	}
@@ -102,7 +102,7 @@ func (o *User) GetUsername() string {
 // GetUsernameOk returns a tuple with the Username field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetUsernameOk() (*string, bool) {
-	if o == nil || isNil(o.Username) {
+	if o == nil || IsNil(o.Username) {
 		return nil, false
 	}
 	return o.Username, true
@@ -110,7 +110,7 @@ func (o *User) GetUsernameOk() (*string, bool) {
 
 // HasUsername returns a boolean if a field has been set.
 func (o *User) HasUsername() bool {
-	if o != nil && !isNil(o.Username) {
+	if o != nil && !IsNil(o.Username) {
 		return true
 	}
 
@@ -124,7 +124,7 @@ func (o *User) SetUsername(v string) {
 
 // GetFirstName returns the FirstName field value if set, zero value otherwise.
 func (o *User) GetFirstName() string {
-	if o == nil || isNil(o.FirstName) {
+	if o == nil || IsNil(o.FirstName) {
 		var ret string
 		return ret
 	}
@@ -134,7 +134,7 @@ func (o *User) GetFirstName() string {
 // GetFirstNameOk returns a tuple with the FirstName field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetFirstNameOk() (*string, bool) {
-	if o == nil || isNil(o.FirstName) {
+	if o == nil || IsNil(o.FirstName) {
 		return nil, false
 	}
 	return o.FirstName, true
@@ -142,7 +142,7 @@ func (o *User) GetFirstNameOk() (*string, bool) {
 
 // HasFirstName returns a boolean if a field has been set.
 func (o *User) HasFirstName() bool {
-	if o != nil && !isNil(o.FirstName) {
+	if o != nil && !IsNil(o.FirstName) {
 		return true
 	}
 
@@ -156,7 +156,7 @@ func (o *User) SetFirstName(v string) {
 
 // GetLastName returns the LastName field value if set, zero value otherwise.
 func (o *User) GetLastName() string {
-	if o == nil || isNil(o.LastName) {
+	if o == nil || IsNil(o.LastName) {
 		var ret string
 		return ret
 	}
@@ -166,7 +166,7 @@ func (o *User) GetLastName() string {
 // GetLastNameOk returns a tuple with the LastName field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetLastNameOk() (*string, bool) {
-	if o == nil || isNil(o.LastName) {
+	if o == nil || IsNil(o.LastName) {
 		return nil, false
 	}
 	return o.LastName, true
@@ -174,7 +174,7 @@ func (o *User) GetLastNameOk() (*string, bool) {
 
 // HasLastName returns a boolean if a field has been set.
 func (o *User) HasLastName() bool {
-	if o != nil && !isNil(o.LastName) {
+	if o != nil && !IsNil(o.LastName) {
 		return true
 	}
 
@@ -188,7 +188,7 @@ func (o *User) SetLastName(v string) {
 
 // GetEmail returns the Email field value if set, zero value otherwise.
 func (o *User) GetEmail() string {
-	if o == nil || isNil(o.Email) {
+	if o == nil || IsNil(o.Email) {
 		var ret string
 		return ret
 	}
@@ -198,7 +198,7 @@ func (o *User) GetEmail() string {
 // GetEmailOk returns a tuple with the Email field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetEmailOk() (*string, bool) {
-	if o == nil || isNil(o.Email) {
+	if o == nil || IsNil(o.Email) {
 		return nil, false
 	}
 	return o.Email, true
@@ -206,7 +206,7 @@ func (o *User) GetEmailOk() (*string, bool) {
 
 // HasEmail returns a boolean if a field has been set.
 func (o *User) HasEmail() bool {
-	if o != nil && !isNil(o.Email) {
+	if o != nil && !IsNil(o.Email) {
 		return true
 	}
 
@@ -220,7 +220,7 @@ func (o *User) SetEmail(v string) {
 
 // GetPassword returns the Password field value if set, zero value otherwise.
 func (o *User) GetPassword() string {
-	if o == nil || isNil(o.Password) {
+	if o == nil || IsNil(o.Password) {
 		var ret string
 		return ret
 	}
@@ -230,7 +230,7 @@ func (o *User) GetPassword() string {
 // GetPasswordOk returns a tuple with the Password field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetPasswordOk() (*string, bool) {
-	if o == nil || isNil(o.Password) {
+	if o == nil || IsNil(o.Password) {
 		return nil, false
 	}
 	return o.Password, true
@@ -238,7 +238,7 @@ func (o *User) GetPasswordOk() (*string, bool) {
 
 // HasPassword returns a boolean if a field has been set.
 func (o *User) HasPassword() bool {
-	if o != nil && !isNil(o.Password) {
+	if o != nil && !IsNil(o.Password) {
 		return true
 	}
 
@@ -252,7 +252,7 @@ func (o *User) SetPassword(v string) {
 
 // GetPhone returns the Phone field value if set, zero value otherwise.
 func (o *User) GetPhone() string {
-	if o == nil || isNil(o.Phone) {
+	if o == nil || IsNil(o.Phone) {
 		var ret string
 		return ret
 	}
@@ -262,7 +262,7 @@ func (o *User) GetPhone() string {
 // GetPhoneOk returns a tuple with the Phone field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetPhoneOk() (*string, bool) {
-	if o == nil || isNil(o.Phone) {
+	if o == nil || IsNil(o.Phone) {
 		return nil, false
 	}
 	return o.Phone, true
@@ -270,7 +270,7 @@ func (o *User) GetPhoneOk() (*string, bool) {
 
 // HasPhone returns a boolean if a field has been set.
 func (o *User) HasPhone() bool {
-	if o != nil && !isNil(o.Phone) {
+	if o != nil && !IsNil(o.Phone) {
 		return true
 	}
 
@@ -284,7 +284,7 @@ func (o *User) SetPhone(v string) {
 
 // GetUserStatus returns the UserStatus field value if set, zero value otherwise.
 func (o *User) GetUserStatus() int32 {
-	if o == nil || isNil(o.UserStatus) {
+	if o == nil || IsNil(o.UserStatus) {
 		var ret int32
 		return ret
 	}
@@ -294,7 +294,7 @@ func (o *User) GetUserStatus() int32 {
 // GetUserStatusOk returns a tuple with the UserStatus field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetUserStatusOk() (*int32, bool) {
-	if o == nil || isNil(o.UserStatus) {
+	if o == nil || IsNil(o.UserStatus) {
 		return nil, false
 	}
 	return o.UserStatus, true
@@ -302,7 +302,7 @@ func (o *User) GetUserStatusOk() (*int32, bool) {
 
 // HasUserStatus returns a boolean if a field has been set.
 func (o *User) HasUserStatus() bool {
-	if o != nil && !isNil(o.UserStatus) {
+	if o != nil && !IsNil(o.UserStatus) {
 		return true
 	}
 
@@ -316,7 +316,7 @@ func (o *User) SetUserStatus(v int32) {
 
 // GetArbitraryObject returns the ArbitraryObject field value if set, zero value otherwise.
 func (o *User) GetArbitraryObject() map[string]interface{} {
-	if o == nil || isNil(o.ArbitraryObject) {
+	if o == nil || IsNil(o.ArbitraryObject) {
 		var ret map[string]interface{}
 		return ret
 	}
@@ -326,7 +326,7 @@ func (o *User) GetArbitraryObject() map[string]interface{} {
 // GetArbitraryObjectOk returns a tuple with the ArbitraryObject field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *User) GetArbitraryObjectOk() (map[string]interface{}, bool) {
-	if o == nil || isNil(o.ArbitraryObject) {
+	if o == nil || IsNil(o.ArbitraryObject) {
 		return map[string]interface{}{}, false
 	}
 	return o.ArbitraryObject, true
@@ -334,7 +334,7 @@ func (o *User) GetArbitraryObjectOk() (map[string]interface{}, bool) {
 
 // HasArbitraryObject returns a boolean if a field has been set.
 func (o *User) HasArbitraryObject() bool {
-	if o != nil && !isNil(o.ArbitraryObject) {
+	if o != nil && !IsNil(o.ArbitraryObject) {
 		return true
 	}
 
@@ -359,7 +359,7 @@ func (o *User) GetArbitraryNullableObject() map[string]interface{} {
 // and a boolean to check if the value has been set.
 // NOTE: If the value is an explicit nil, `nil, true` will be returned
 func (o *User) GetArbitraryNullableObjectOk() (map[string]interface{}, bool) {
-	if o == nil || isNil(o.ArbitraryNullableObject) {
+	if o == nil || IsNil(o.ArbitraryNullableObject) {
 		return map[string]interface{}{}, false
 	}
 	return o.ArbitraryNullableObject, true
@@ -367,7 +367,7 @@ func (o *User) GetArbitraryNullableObjectOk() (map[string]interface{}, bool) {
 
 // HasArbitraryNullableObject returns a boolean if a field has been set.
 func (o *User) HasArbitraryNullableObject() bool {
-	if o != nil && isNil(o.ArbitraryNullableObject) {
+	if o != nil && IsNil(o.ArbitraryNullableObject) {
 		return true
 	}
 
@@ -392,7 +392,7 @@ func (o *User) GetArbitraryTypeValue() interface{} {
 // and a boolean to check if the value has been set.
 // NOTE: If the value is an explicit nil, `nil, true` will be returned
 func (o *User) GetArbitraryTypeValueOk() (*interface{}, bool) {
-	if o == nil || isNil(o.ArbitraryTypeValue) {
+	if o == nil || IsNil(o.ArbitraryTypeValue) {
 		return nil, false
 	}
 	return &o.ArbitraryTypeValue, true
@@ -400,7 +400,7 @@ func (o *User) GetArbitraryTypeValueOk() (*interface{}, bool) {
 
 // HasArbitraryTypeValue returns a boolean if a field has been set.
 func (o *User) HasArbitraryTypeValue() bool {
-	if o != nil && isNil(o.ArbitraryTypeValue) {
+	if o != nil && IsNil(o.ArbitraryTypeValue) {
 		return true
 	}
 
@@ -425,7 +425,7 @@ func (o *User) GetArbitraryNullableTypeValue() interface{} {
 // and a boolean to check if the value has been set.
 // NOTE: If the value is an explicit nil, `nil, true` will be returned
 func (o *User) GetArbitraryNullableTypeValueOk() (*interface{}, bool) {
-	if o == nil || isNil(o.ArbitraryNullableTypeValue) {
+	if o == nil || IsNil(o.ArbitraryNullableTypeValue) {
 		return nil, false
 	}
 	return &o.ArbitraryNullableTypeValue, true
@@ -433,7 +433,7 @@ func (o *User) GetArbitraryNullableTypeValueOk() (*interface{}, bool) {
 
 // HasArbitraryNullableTypeValue returns a boolean if a field has been set.
 func (o *User) HasArbitraryNullableTypeValue() bool {
-	if o != nil && isNil(o.ArbitraryNullableTypeValue) {
+	if o != nil && IsNil(o.ArbitraryNullableTypeValue) {
 		return true
 	}
 
@@ -455,31 +455,31 @@ func (o User) MarshalJSON() ([]byte, error) {
 
 func (o User) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Id) {
+	if !IsNil(o.Id) {
 		toSerialize["id"] = o.Id
 	}
-	if !isNil(o.Username) {
+	if !IsNil(o.Username) {
 		toSerialize["username"] = o.Username
 	}
-	if !isNil(o.FirstName) {
+	if !IsNil(o.FirstName) {
 		toSerialize["firstName"] = o.FirstName
 	}
-	if !isNil(o.LastName) {
+	if !IsNil(o.LastName) {
 		toSerialize["lastName"] = o.LastName
 	}
-	if !isNil(o.Email) {
+	if !IsNil(o.Email) {
 		toSerialize["email"] = o.Email
 	}
-	if !isNil(o.Password) {
+	if !IsNil(o.Password) {
 		toSerialize["password"] = o.Password
 	}
-	if !isNil(o.Phone) {
+	if !IsNil(o.Phone) {
 		toSerialize["phone"] = o.Phone
 	}
-	if !isNil(o.UserStatus) {
+	if !IsNil(o.UserStatus) {
 		toSerialize["userStatus"] = o.UserStatus
 	}
-	if !isNil(o.ArbitraryObject) {
+	if !IsNil(o.ArbitraryObject) {
 		toSerialize["arbitraryObject"] = o.ArbitraryObject
 	}
 	if o.ArbitraryNullableObject != nil {
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_whale.go b/samples/openapi3/client/petstore/go/go-petstore/model_whale.go
index f90923f1046..8ee96e3aea3 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_whale.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_whale.go
@@ -47,7 +47,7 @@ func NewWhaleWithDefaults() *Whale {
 
 // GetHasBaleen returns the HasBaleen field value if set, zero value otherwise.
 func (o *Whale) GetHasBaleen() bool {
-	if o == nil || isNil(o.HasBaleen) {
+	if o == nil || IsNil(o.HasBaleen) {
 		var ret bool
 		return ret
 	}
@@ -57,7 +57,7 @@ func (o *Whale) GetHasBaleen() bool {
 // GetHasBaleenOk returns a tuple with the HasBaleen field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Whale) GetHasBaleenOk() (*bool, bool) {
-	if o == nil || isNil(o.HasBaleen) {
+	if o == nil || IsNil(o.HasBaleen) {
 		return nil, false
 	}
 	return o.HasBaleen, true
@@ -65,7 +65,7 @@ func (o *Whale) GetHasBaleenOk() (*bool, bool) {
 
 // HasHasBaleen returns a boolean if a field has been set.
 func (o *Whale) HasHasBaleen() bool {
-	if o != nil && !isNil(o.HasBaleen) {
+	if o != nil && !IsNil(o.HasBaleen) {
 		return true
 	}
 
@@ -79,7 +79,7 @@ func (o *Whale) SetHasBaleen(v bool) {
 
 // GetHasTeeth returns the HasTeeth field value if set, zero value otherwise.
 func (o *Whale) GetHasTeeth() bool {
-	if o == nil || isNil(o.HasTeeth) {
+	if o == nil || IsNil(o.HasTeeth) {
 		var ret bool
 		return ret
 	}
@@ -89,7 +89,7 @@ func (o *Whale) GetHasTeeth() bool {
 // GetHasTeethOk returns a tuple with the HasTeeth field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Whale) GetHasTeethOk() (*bool, bool) {
-	if o == nil || isNil(o.HasTeeth) {
+	if o == nil || IsNil(o.HasTeeth) {
 		return nil, false
 	}
 	return o.HasTeeth, true
@@ -97,7 +97,7 @@ func (o *Whale) GetHasTeethOk() (*bool, bool) {
 
 // HasHasTeeth returns a boolean if a field has been set.
 func (o *Whale) HasHasTeeth() bool {
-	if o != nil && !isNil(o.HasTeeth) {
+	if o != nil && !IsNil(o.HasTeeth) {
 		return true
 	}
 
@@ -143,10 +143,10 @@ func (o Whale) MarshalJSON() ([]byte, error) {
 
 func (o Whale) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.HasBaleen) {
+	if !IsNil(o.HasBaleen) {
 		toSerialize["hasBaleen"] = o.HasBaleen
 	}
-	if !isNil(o.HasTeeth) {
+	if !IsNil(o.HasTeeth) {
 		toSerialize["hasTeeth"] = o.HasTeeth
 	}
 	toSerialize["className"] = o.ClassName
diff --git a/samples/openapi3/client/petstore/go/go-petstore/model_zebra.go b/samples/openapi3/client/petstore/go/go-petstore/model_zebra.go
index 76106e1eb54..3349c9470cf 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/model_zebra.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/model_zebra.go
@@ -46,7 +46,7 @@ func NewZebraWithDefaults() *Zebra {
 
 // GetType returns the Type field value if set, zero value otherwise.
 func (o *Zebra) GetType() string {
-	if o == nil || isNil(o.Type) {
+	if o == nil || IsNil(o.Type) {
 		var ret string
 		return ret
 	}
@@ -56,7 +56,7 @@ func (o *Zebra) GetType() string {
 // GetTypeOk returns a tuple with the Type field value if set, nil otherwise
 // and a boolean to check if the value has been set.
 func (o *Zebra) GetTypeOk() (*string, bool) {
-	if o == nil || isNil(o.Type) {
+	if o == nil || IsNil(o.Type) {
 		return nil, false
 	}
 	return o.Type, true
@@ -64,7 +64,7 @@ func (o *Zebra) GetTypeOk() (*string, bool) {
 
 // HasType returns a boolean if a field has been set.
 func (o *Zebra) HasType() bool {
-	if o != nil && !isNil(o.Type) {
+	if o != nil && !IsNil(o.Type) {
 		return true
 	}
 
@@ -110,7 +110,7 @@ func (o Zebra) MarshalJSON() ([]byte, error) {
 
 func (o Zebra) ToMap() (map[string]interface{}, error) {
 	toSerialize := map[string]interface{}{}
-	if !isNil(o.Type) {
+	if !IsNil(o.Type) {
 		toSerialize["type"] = o.Type
 	}
 	toSerialize["className"] = o.ClassName
diff --git a/samples/openapi3/client/petstore/go/go-petstore/utils.go b/samples/openapi3/client/petstore/go/go-petstore/utils.go
index 9e3eb715da4..87f943e53f4 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/utils.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/utils.go
@@ -328,8 +328,8 @@ func (v *NullableTime) UnmarshalJSON(src []byte) error {
 	return json.Unmarshal(src, &v.value)
 }
 
-// isNil checks if an input is nil
-func isNil(i interface{}) bool {
+// IsNil checks if an input is nil
+func IsNil(i interface{}) bool {
 	if i == nil {
 		return true
 	}