diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultGenerator.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultGenerator.java
index 9a2a47853e..e6e1499a2e 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultGenerator.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultGenerator.java
@@ -262,6 +262,13 @@ public class DefaultGenerator extends AbstractGenerator implements Generator {
                     operation.put("classVarName", config.toApiVarName(tag));
                     operation.put("importPath", config.toApiImport(tag));
 
+                    // Pass sortParamsByRequiredFlag through to the Mustache template...
+                    boolean sortParamsByRequiredFlag = true;
+                    if (this.config.additionalProperties().containsKey(CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG)) {
+                        sortParamsByRequiredFlag = Boolean.valueOf((String)this.config.additionalProperties().get(CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG).toString());
+                    }
+                    operation.put("sortParamsByRequiredFlag", sortParamsByRequiredFlag);
+
                     processMimeTypes(swagger.getConsumes(), operation, "consumes");
                     processMimeTypes(swagger.getProduces(), operation, "produces");
 
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java
index 7156df2d4e..30ab4c2382 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java
@@ -82,7 +82,7 @@ public class CSharpClientCodegen extends DefaultCodegen implements CodegenConfig
         cliOptions.clear();
         cliOptions.add(new CliOption(CodegenConstants.PACKAGE_NAME, "C# package name (convention: Camel.Case), default: IO.Swagger"));
         cliOptions.add(new CliOption(CodegenConstants.PACKAGE_VERSION, "C# package version, default: 1.0.0"));
-
+        cliOptions.add(new CliOption(CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG, CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG_DESC));
     }
 
     @Override
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java
index 8277aa20f1..55bde04815 100755
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java
@@ -66,6 +66,7 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
         cliOptions.add(new CliOption(CodegenConstants.PACKAGE_NAME, "python package name (convention: snake_case)," +
                 " default: swagger_client"));
         cliOptions.add(new CliOption(CodegenConstants.PACKAGE_VERSION, "python package version, default: 1.0.0"));
+        cliOptions.add(new CliOption(CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG, CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG_DESC));
     }
 
     @Override
diff --git a/modules/swagger-codegen/src/main/resources/python/api.mustache b/modules/swagger-codegen/src/main/resources/python/api.mustache
index b076fa5d3e..474cf84f35 100644
--- a/modules/swagger-codegen/src/main/resources/python/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/python/api.mustache
@@ -47,7 +47,7 @@ class {{classname}}(object):
             self.api_client = config.api_client
 {{#operation}}
 
-    def {{nickname}}(self, {{#allParams}}{{#required}}{{paramName}}, {{/required}}{{/allParams}}**kwargs):
+    def {{nickname}}(self, {{#sortParamsByRequiredFlag}}{{#allParams}}{{#required}}{{paramName}}, {{/required}}{{/allParams}}{{/sortParamsByRequiredFlag}}**kwargs):
         """
         {{{summary}}}
         {{{notes}}}
@@ -58,7 +58,12 @@ class {{classname}}(object):
         >>> def callback_function(response):
         >>>     pprint(response)
         >>>
+{{#sortParamsByRequiredFlag}}
         >>> thread = api.{{nickname}}({{#allParams}}{{#required}}{{paramName}}, {{/required}}{{/allParams}}callback=callback_function)
+{{/sortParamsByRequiredFlag}}
+{{^sortParamsByRequiredFlag}}
+        >>> thread = api.{{nickname}}({{#allParams}}{{#required}}{{paramName}}={{paramName}}_value, {{/required}}{{/allParams}}callback=callback_function)
+{{/sortParamsByRequiredFlag}}
 
         :param callback function: The callback function
             for asynchronous request. (optional)
@@ -69,13 +74,6 @@ class {{classname}}(object):
                  If the method is called asynchronously,
                  returns the request thread.
         """
-{{#allParams}}
-{{#required}}
-        # verify the required parameter '{{paramName}}' is set
-        if {{paramName}} is None:
-            raise ValueError("Missing the required parameter `{{paramName}}` when calling `{{nickname}}`")
-{{/required}}
-{{/allParams}}
 
         all_params = [{{#allParams}}'{{paramName}}'{{#hasMore}}, {{/hasMore}}{{/allParams}}]
         all_params.append('callback')
@@ -90,6 +88,14 @@ class {{classname}}(object):
             params[key] = val
         del params['kwargs']
 
+{{#allParams}}
+{{#required}}
+        # verify the required parameter '{{paramName}}' is set
+        if ('{{paramName}}' not in params) or (params['{{paramName}}'] is None):
+            raise ValueError("Missing the required parameter `{{paramName}}` when calling `{{nickname}}`")
+{{/required}}
+{{/allParams}}
+
         resource_path = '{{path}}'.replace('{format}', 'json')
         method = '{{httpMethod}}'
 
diff --git a/modules/swagger-codegen/src/test/java/io/swagger/codegen/csharp/CSharpClientOptionsTest.java b/modules/swagger-codegen/src/test/java/io/swagger/codegen/csharp/CSharpClientOptionsTest.java
index 5a64e676dc..5fc990fabc 100644
--- a/modules/swagger-codegen/src/test/java/io/swagger/codegen/csharp/CSharpClientOptionsTest.java
+++ b/modules/swagger-codegen/src/test/java/io/swagger/codegen/csharp/CSharpClientOptionsTest.java
@@ -38,6 +38,7 @@ public class CSharpClientOptionsTest extends AbstractOptionsTest {
         ImmutableMap.Builder<String, String> builder = new ImmutableMap.Builder<String, String>();
         return builder.put(CodegenConstants.PACKAGE_NAME, PACKAGE_NAME_VALUE)
                 .put(CodegenConstants.PACKAGE_VERSION, PACKAGE_VERSION_VALUE)
+                .put(CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG, "true")
                 .build();
     }
 }
diff --git a/modules/swagger-codegen/src/test/java/io/swagger/codegen/python/PythonClientOptionsTest.java b/modules/swagger-codegen/src/test/java/io/swagger/codegen/python/PythonClientOptionsTest.java
index 645471789e..6a96efd5c7 100644
--- a/modules/swagger-codegen/src/test/java/io/swagger/codegen/python/PythonClientOptionsTest.java
+++ b/modules/swagger-codegen/src/test/java/io/swagger/codegen/python/PythonClientOptionsTest.java
@@ -38,6 +38,7 @@ public class PythonClientOptionsTest extends AbstractOptionsTest {
         ImmutableMap.Builder<String, String> builder = new ImmutableMap.Builder<String, String>();
         return builder.put(CodegenConstants.PACKAGE_NAME, PACKAGE_NAME_VALUE)
                 .put(CodegenConstants.PACKAGE_VERSION, PACKAGE_VERSION_VALUE)
+                .put(CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG, "true")
                 .build();
     }
 }