Add polymorphism support for python (#6066)

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java

@@ -41,7 +41,8 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
         // clear import mapping (from default generator) as python does not use it
         // at the moment
         importMapping.clear();
-
+        
+        supportsInheritance = true;
         modelPackage = "models";
         apiPackage = "api";
         outputFolder = "generated-code" + File.separatorChar + "python";