[Python] Add attribute_map to simple model (#6669)

* [python] Add missing attribute_map definition

* regenerated

modules/openapi-generator/src/main/resources/python/python-experimental/model_templates/model_simple.mustache

@@ -11,6 +11,8 @@ class {{unescapedDescription}}(ModelSimple):
 
 {{> python-experimental/model_templates/classvars }}
 
+    attribute_map = {}
+
     _composed_schemas = None
 
 {{> python-experimental/model_templates/method_init_normal}}

samples/client/petstore/python-experimental/petstore_api/model/animal_farm.py

@@ -88,6 +88,8 @@ class AnimalFarm(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([

samples/client/petstore/python-experimental/petstore_api/model/enum_class.py

@@ -88,6 +88,8 @@ class EnumClass(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([

samples/client/petstore/python-experimental/petstore_api/model/outer_enum.py

@@ -88,6 +88,8 @@ class OuterEnum(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([

samples/client/petstore/python-experimental/petstore_api/model/outer_number.py

@@ -87,6 +87,8 @@ class OuterNumber(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([

samples/openapi3/client/petstore/python-experimental/petstore_api/model/animal_farm.py

@@ -88,6 +88,8 @@ class AnimalFarm(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([

samples/openapi3/client/petstore/python-experimental/petstore_api/model/array_of_enums.py

@@ -88,6 +88,8 @@ class ArrayOfEnums(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([

samples/openapi3/client/petstore/python-experimental/petstore_api/model/enum_class.py

@@ -88,6 +88,8 @@ class EnumClass(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([

samples/openapi3/client/petstore/python-experimental/petstore_api/model/outer_enum.py

@@ -89,6 +89,8 @@ class OuterEnum(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([

samples/openapi3/client/petstore/python-experimental/petstore_api/model/outer_enum_default_value.py

@@ -88,6 +88,8 @@ class OuterEnumDefaultValue(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([

samples/openapi3/client/petstore/python-experimental/petstore_api/model/outer_enum_integer.py

@@ -88,6 +88,8 @@ class OuterEnumInteger(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([

samples/openapi3/client/petstore/python-experimental/petstore_api/model/outer_enum_integer_default_value.py

@@ -88,6 +88,8 @@ class OuterEnumIntegerDefaultValue(ModelSimple):
     def discriminator():
         return None
 
+    attribute_map = {}
+
     _composed_schemas = None
 
     required_properties = set([