diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/FlaskConnexionCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/FlaskConnexionCodegen.java
index 61a624648bac..050f21b8eff9 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/FlaskConnexionCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/FlaskConnexionCodegen.java
@@ -620,11 +620,26 @@ public class FlaskConnexionCodegen extends DefaultCodegen implements CodegenConf
 
     @Override
     public String toModelImport(String name) {
-        String modelImport = "from ";
-        if (!"".equals(modelPackage())) {
-            modelImport += modelPackage() + ".";
+        String modelImport;
+        if (StringUtils.startsWithAny(name,"import", "from")) {
+            modelImport = name;
+        } else {
+            modelImport = "from ";
+            if (!"".equals(modelPackage())) {
+                modelImport += modelPackage() + ".";
+            }
+            modelImport += toModelFilename(name)+ " import " + name;
         }
-        modelImport += toModelFilename(name)+ " import " + name;
         return modelImport;
     }
+
+    @Override
+    public void postProcessModelProperty(CodegenModel model, CodegenProperty property){
+        if (StringUtils.isNotEmpty(property.pattern)) {
+            addImport(model, "import re");
+        }
+    }
+
+
+
 }
diff --git a/modules/swagger-codegen/src/main/resources/swift/Models.mustache b/modules/swagger-codegen/src/main/resources/swift/Models.mustache
index ed9e12a79b51..3892a4fd3181 100644
--- a/modules/swagger-codegen/src/main/resources/swift/Models.mustache
+++ b/modules/swagger-codegen/src/main/resources/swift/Models.mustache
@@ -121,6 +121,7 @@ class Decoders {
                 "yyyy-MM-dd'T'HH:mm:ss.SSS"
             ].map { (format: String) -> NSDateFormatter in
                 let formatter = NSDateFormatter()
+                formatter.locale = NSLocale(localeIdentifier:"en_US_POSIX")
                 formatter.dateFormat = format
                 return formatter
             }
diff --git a/samples/client/petstore/swift/default/PetstoreClient/Classes/Swaggers/Models.swift b/samples/client/petstore/swift/default/PetstoreClient/Classes/Swaggers/Models.swift
index c9c48bf10e39..e87ae45017f9 100644
--- a/samples/client/petstore/swift/default/PetstoreClient/Classes/Swaggers/Models.swift
+++ b/samples/client/petstore/swift/default/PetstoreClient/Classes/Swaggers/Models.swift
@@ -121,6 +121,7 @@ class Decoders {
                 "yyyy-MM-dd'T'HH:mm:ss.SSS"
             ].map { (format: String) -> NSDateFormatter in
                 let formatter = NSDateFormatter()
+                formatter.locale = NSLocale(localeIdentifier:"en_US_POSIX")
                 formatter.dateFormat = format
                 return formatter
             }
diff --git a/samples/client/petstore/swift/promisekit/PetstoreClient/Classes/Swaggers/Models.swift b/samples/client/petstore/swift/promisekit/PetstoreClient/Classes/Swaggers/Models.swift
index c9c48bf10e39..e87ae45017f9 100644
--- a/samples/client/petstore/swift/promisekit/PetstoreClient/Classes/Swaggers/Models.swift
+++ b/samples/client/petstore/swift/promisekit/PetstoreClient/Classes/Swaggers/Models.swift
@@ -121,6 +121,7 @@ class Decoders {
                 "yyyy-MM-dd'T'HH:mm:ss.SSS"
             ].map { (format: String) -> NSDateFormatter in
                 let formatter = NSDateFormatter()
+                formatter.locale = NSLocale(localeIdentifier:"en_US_POSIX")
                 formatter.dateFormat = format
                 return formatter
             }
diff --git a/samples/client/petstore/swift/rxswift/PetstoreClient/Classes/Swaggers/Models.swift b/samples/client/petstore/swift/rxswift/PetstoreClient/Classes/Swaggers/Models.swift
index c9c48bf10e39..e87ae45017f9 100644
--- a/samples/client/petstore/swift/rxswift/PetstoreClient/Classes/Swaggers/Models.swift
+++ b/samples/client/petstore/swift/rxswift/PetstoreClient/Classes/Swaggers/Models.swift
@@ -121,6 +121,7 @@ class Decoders {
                 "yyyy-MM-dd'T'HH:mm:ss.SSS"
             ].map { (format: String) -> NSDateFormatter in
                 let formatter = NSDateFormatter()
+                formatter.locale = NSLocale(localeIdentifier:"en_US_POSIX")
                 formatter.dateFormat = format
                 return formatter
             }