diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/GoClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/GoClientCodegen.java
index 9681f435534..e36b288f0be 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/GoClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/GoClientCodegen.java
@@ -301,6 +301,11 @@ public void postProcessParameter(CodegenParameter parameter){
         StringBuilder sb = new StringBuilder(parameter.paramName);
         sb.setCharAt(0, Character.toUpperCase(firstChar));
         parameter.vendorExtensions.put("x-exportParamName", sb.toString());
+
+	// Dates are not a primitive. Not sure how this is getting flagged as such.
+	if (parameter.isDate != null|| parameter.isDateTime != null || parameter.isFile != null) {
+            parameter.isPrimitiveType = Boolean.FALSE;
+        }
     }
 
 
diff --git a/modules/swagger-codegen/src/main/resources/go/api.mustache b/modules/swagger-codegen/src/main/resources/go/api.mustache
index ef388bcf278..44d54828d35 100644
--- a/modules/swagger-codegen/src/main/resources/go/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/go/api.mustache
@@ -34,10 +34,10 @@ func New{{classname}}WithBasePath(basePath string) *{{classname}} {
  * {{summary}}{{#notes}}
  * {{notes}}{{/notes}}
  *
-{{#allParams}} * @param {{paramName}} {{description}}
-{{/allParams}} * @return {{#returnType}}{{^isListContainer}}*{{/isListContainer}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}
+{{#allParams}} * @param {{paramName}}{{^required}}{{#isPrimitiveType}}(nil){{/isPrimitiveType}}{{/required}} {{description}} 
+{{/allParams}} * @return {{#returnType}}{{^isListContainer}}*{{/isListContainer}}{{{returnType}}}{{/returnType}}{{^returnType}}nil{{/returnType}}
  */
-func (a {{{classname}}}) {{{nickname}}}({{#allParams}}{{paramName}} {{{dataType}}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) ({{#returnType}}{{^isListContainer}}*{{/isListContainer}}{{{returnType}}}, {{/returnType}}*APIResponse, error) {
+func (a {{{classname}}}) {{{nickname}}}({{#allParams}}{{paramName}} {{#required}}{{{dataType}}}{{/required}}{{^required}}{{#isPrimitiveType}}interface{}{{/isPrimitiveType}}{{^isPrimitiveType}}{{{dataType}}}{{/isPrimitiveType}}{{/required}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) ({{#returnType}}{{^isListContainer}}*{{/isListContainer}}{{{returnType}}}, {{/returnType}}*APIResponse, error) {
 
 	var localVarHttpMethod = strings.ToUpper("{{httpMethod}}")
 	// create path and map variables
@@ -79,21 +79,30 @@ func (a {{{classname}}}) {{{nickname}}}({{#allParams}}{{paramName}} {{{dataType}
 	for key := range a.Configuration.DefaultHeader {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
+
+{{#allParams}}
+{{^required}}
+{{#isPrimitiveType}}
+	if err := a.Configuration.APIClient.typeCheckParameter({{paramName}}, "{{{dataType}}}", "{{paramName}}"); err != nil {
+		return {{#returnType}}nil, {{/returnType}} nil, err
+	}
+{{/isPrimitiveType}}
+{{/required}}
+{{/allParams}}
 	{{#hasQueryParams}}
 	{{#queryParams}}
+	{{^required}}
+	if {{paramName}} != nil {
+    {{/required}}
 	{{#isListContainer}}
-	var collectionFormat = "{{#collectionFormat}}{{collectionFormat}}{{/collectionFormat}}"
-	if collectionFormat == "multi" {
-		for _, value := range {{paramName}} {
-			localVarQueryParams.Add("{{baseName}}", value)
-		}
-	} else {
-		localVarQueryParams.Add("{{baseName}}", a.Configuration.APIClient.ParameterToString({{paramName}}, collectionFormat))
-	}
+		localVarQueryParams.Add("{{baseName}}", a.Configuration.APIClient.parameterToString({{paramName}}, "{{collectionFormat}}"))
 	{{/isListContainer}}
 	{{^isListContainer}}
-		localVarQueryParams.Add("{{baseName}}", a.Configuration.APIClient.ParameterToString({{paramName}}, ""))
+		localVarQueryParams.Add("{{baseName}}", a.Configuration.APIClient.parameterToString({{paramName}}, ""))
 	{{/isListContainer}}
+    {{^required}}
+	}
+    {{/required}}
 	{{/queryParams}}
 	{{/hasQueryParams}}
 
@@ -120,7 +129,7 @@ func (a {{{classname}}}) {{{nickname}}}({{#allParams}}{{paramName}} {{{dataType}
 {{#hasHeaderParams}}
 {{#headerParams}}
 	// header params "{{baseName}}"
-	localVarHeaderParams["{{baseName}}"] = a.Configuration.APIClient.ParameterToString({{paramName}}, "")
+	localVarHeaderParams["{{baseName}}"] = a.Configuration.APIClient.parameterToString({{paramName}}, "")
 {{/headerParams}}
 {{/hasHeaderParams}}
 {{#hasFormParams}}
@@ -131,7 +140,7 @@ func (a {{{classname}}}) {{{nickname}}}({{#allParams}}{{paramName}} {{{dataType}
 	localVarFileName = file.Name()
 {{/isFile}}
 {{^isFile}}
-	localVarFormParams["{{paramName}}"] = a.Configuration.APIClient.ParameterToString({{paramName}}, "")
+	localVarFormParams["{{paramName}}"] = a.Configuration.APIClient.parameterToString({{paramName}}, "")
 {{/isFile}}
 {{/formParams}}
 {{/hasFormParams}}
diff --git a/modules/swagger-codegen/src/main/resources/go/api_client.mustache b/modules/swagger-codegen/src/main/resources/go/api_client.mustache
index a92c7631202..40703618dd2 100644
--- a/modules/swagger-codegen/src/main/resources/go/api_client.mustache
+++ b/modules/swagger-codegen/src/main/resources/go/api_client.mustache
@@ -8,6 +8,7 @@ import (
 	"reflect"
 	"strings"
 	"net/url"
+    "errors"
 	"io/ioutil"
 	"github.com/go-resty/resty"
 )
@@ -79,22 +80,38 @@ func (c *APIClient) CallAPI(path string, method string,
 	return nil, fmt.Errorf("invalid method %v", method)
 }
 
-func (c *APIClient) ParameterToString(obj interface{},collectionFormat string) string {
-	if reflect.TypeOf(obj).String() == "[]string" {
-		switch	collectionFormat {
-		case "pipes":
-			return strings.Join(obj.([]string), "|")
-		case "ssv":
-			return strings.Join(obj.([]string), " ")
-		case "tsv":
-			return strings.Join(obj.([]string), "\t")	
-		case "csv" :
-			return strings.Join(obj.([]string), ",")
-		}
+func (c *APIClient) parameterToString(obj interface{}, collectionFormat string) string {
+	delimiter := ""
+	switch collectionFormat {
+	case "pipes":
+		delimiter = "|"
+	case "ssv":
+		delimiter = " "
+	case "tsv":
+		delimiter = "\t"
+	case "csv":
+		delimiter = ","
+	}
+
+	if reflect.TypeOf(obj).Kind() == reflect.Slice {
+		return strings.Trim(strings.Replace(fmt.Sprint(obj), " ", delimiter, -1), "[]")
 	}
 
 	return fmt.Sprintf("%v", obj)
 }
+// Verify optional parameters are of the correct type.
+func (c *APIClient) typeCheckParameter(obj interface{}, expected string, name string) error {
+    // Make sure there is an object.
+    if obj == nil {
+        return nil    
+    }
+
+    // Check the type is as expected.
+	if reflect.TypeOf(obj).String() != expected {
+        return errors.New(fmt.Sprintf("Expected %s to be of type %s but received %s.", name, expected, reflect.TypeOf(obj).String()))
+	}
+	return nil
+}
 
 func (c *APIClient) prepareClient() *resty.Client {
 
diff --git a/samples/client/petstore/go/go-petstore/README.md b/samples/client/petstore/go/go-petstore/README.md
index 164eaf91c07..248b6fdc8f8 100644
--- a/samples/client/petstore/go/go-petstore/README.md
+++ b/samples/client/petstore/go/go-petstore/README.md
@@ -24,6 +24,7 @@ Class | Method | HTTP request | Description
 *FakeApi* | [**TestClientModel**](docs/FakeApi.md#testclientmodel) | **Patch** /fake | To test \"client\" model
 *FakeApi* | [**TestEndpointParameters**](docs/FakeApi.md#testendpointparameters) | **Post** /fake | Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
 *FakeApi* | [**TestEnumParameters**](docs/FakeApi.md#testenumparameters) | **Get** /fake | To test enum parameters
+*Fake_classname_tags123Api* | [**TestClassname**](docs/Fake_classname_tags123Api.md#testclassname) | **Patch** /fake_classname_test | To test class name in snake case
 *PetApi* | [**AddPet**](docs/PetApi.md#addpet) | **Post** /pet | Add a new pet to the store
 *PetApi* | [**DeletePet**](docs/PetApi.md#deletepet) | **Delete** /pet/{petId} | Deletes a pet
 *PetApi* | [**FindPetsByStatus**](docs/PetApi.md#findpetsbystatus) | **Get** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/go/go-petstore/api_client.go b/samples/client/petstore/go/go-petstore/api_client.go
index 6196eb5a706..50bdd3fc09e 100644
--- a/samples/client/petstore/go/go-petstore/api_client.go
+++ b/samples/client/petstore/go/go-petstore/api_client.go
@@ -29,7 +29,7 @@ import (
 	"reflect"
 	"strings"
 	"net/url"
-	"io/ioutil"
+    "errors"
 	"github.com/go-resty/resty"
 )
 
@@ -100,22 +100,38 @@ func (c *APIClient) CallAPI(path string, method string,
 	return nil, fmt.Errorf("invalid method %v", method)
 }
 
-func (c *APIClient) ParameterToString(obj interface{},collectionFormat string) string {
-	if reflect.TypeOf(obj).String() == "[]string" {
-		switch	collectionFormat {
-		case "pipes":
-			return strings.Join(obj.([]string), "|")
-		case "ssv":
-			return strings.Join(obj.([]string), " ")
-		case "tsv":
-			return strings.Join(obj.([]string), "\t")	
-		case "csv" :
-			return strings.Join(obj.([]string), ",")
-		}
+func (c *APIClient) parameterToString(obj interface{}, collectionFormat string) string {
+	delimiter := ""
+	switch collectionFormat {
+	case "pipes":
+		delimiter = "|"
+	case "ssv":
+		delimiter = " "
+	case "tsv":
+		delimiter = "\t"
+	case "csv":
+		delimiter = ","
+	}
+
+	if reflect.TypeOf(obj).Kind() == reflect.Slice {
+		return strings.Trim(strings.Replace(fmt.Sprint(obj), " ", delimiter, -1), "[]")
 	}
 
 	return fmt.Sprintf("%v", obj)
 }
+// Verify optional parameters are of the correct type.
+func (c *APIClient) typeCheckParameter(obj interface{}, expected string, name string) error {
+    // Make sure there is an object.
+    if obj == nil {
+        return nil    
+    }
+
+    // Check the type is as expected.
+	if reflect.TypeOf(obj).String() != expected {
+        return errors.New(fmt.Sprintf("Expected %s to be of type %s but received %s.", name, expected, reflect.TypeOf(obj).String()))
+	}
+	return nil
+}
 
 func (c *APIClient) prepareClient() *resty.Client {
 
@@ -129,7 +145,7 @@ func (c *APIClient) prepareClient() *resty.Client {
 	if c.config.Timeout != nil {
 		rClient.SetTimeout(*c.config.Timeout)
 	}
-	rClient.SetLogger(ioutil.Discard)
+
 	return rClient
 }
 
diff --git a/samples/client/petstore/go/go-petstore/docs/FakeApi.md b/samples/client/petstore/go/go-petstore/docs/FakeApi.md
index 63e7fb728fb..f3f9dbbf2d3 100644
--- a/samples/client/petstore/go/go-petstore/docs/FakeApi.md
+++ b/samples/client/petstore/go/go-petstore/docs/FakeApi.md
@@ -37,7 +37,7 @@ No authorization required
 [[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
 
 # **TestEndpointParameters**
-> TestEndpointParameters($number, $double, $patternWithoutDelimiter, $byte_, $integer, $int32_, $int64_, $float, $string_, $binary, $date, $dateTime, $password)
+> TestEndpointParameters($number, $double, $patternWithoutDelimiter, $byte_, $integer, $int32_, $int64_, $float, $string_, $binary, $date, $dateTime, $password, $callback)
 
 Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
 
@@ -58,9 +58,10 @@ Name | Type | Description  | Notes
  **float** | **float32**| None | [optional] 
  **string_** | **string**| None | [optional] 
  **binary** | **string**| None | [optional] 
- **date** | **time.Time**| None | [optional] 
- **dateTime** | **time.Time**| None | [optional] 
+ **date** | [**time.Time**](.md)| None | [optional] 
+ **dateTime** | [**time.Time**](.md)| None | [optional] 
  **password** | **string**| None | [optional] 
+ **callback** | **string**| None | [optional] 
 
 ### Return type
 
@@ -106,8 +107,8 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: application/json
- - **Accept**: application/json
+ - **Content-Type**: */*
+ - **Accept**: */*
 
 [[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/go/go-petstore/docs/Fake_classname_tags123Api.md b/samples/client/petstore/go/go-petstore/docs/Fake_classname_tags123Api.md
new file mode 100644
index 00000000000..bc70731a6d8
--- /dev/null
+++ b/samples/client/petstore/go/go-petstore/docs/Fake_classname_tags123Api.md
@@ -0,0 +1,36 @@
+# \Fake_classname_tags123Api
+
+All URIs are relative to *http://petstore.swagger.io/v2*
+
+Method | HTTP request | Description
+------------- | ------------- | -------------
+[**TestClassname**](Fake_classname_tags123Api.md#TestClassname) | **Patch** /fake_classname_test | To test class name in snake case
+
+
+# **TestClassname**
+> Client TestClassname($body)
+
+To test class name in snake case
+
+
+### Parameters
+
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+ **body** | [**Client**](Client.md)| client model | 
+
+### Return type
+
+[**Client**](Client.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: application/json
+ - **Accept**: application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+
diff --git a/samples/client/petstore/go/go-petstore/fake_api.go b/samples/client/petstore/go/go-petstore/fake_api.go
index f7cb65af821..23832f41fe0 100644
--- a/samples/client/petstore/go/go-petstore/fake_api.go
+++ b/samples/client/petstore/go/go-petstore/fake_api.go
@@ -52,7 +52,7 @@ func NewFakeApiWithBasePath(basePath string) *FakeApi {
 /**
  * To test \"client\" model
  *
- * @param body client model
+ * @param body client model 
  * @return *Client
  */
 func (a FakeApi) TestClientModel(body Client) (*Client, *APIResponse, error) {
@@ -72,6 +72,7 @@ func (a FakeApi) TestClientModel(body Client) (*Client, *APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{ "application/json",  }
 
@@ -114,22 +115,23 @@ func (a FakeApi) TestClientModel(body Client) (*Client, *APIResponse, error) {
  * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
  * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
  *
- * @param number None
- * @param double None
- * @param patternWithoutDelimiter None
- * @param byte_ None
- * @param integer None
- * @param int32_ None
- * @param int64_ None
- * @param float None
- * @param string_ None
- * @param binary None
- * @param date None
- * @param dateTime None
- * @param password None
- * @return void
+ * @param number None 
+ * @param double None 
+ * @param patternWithoutDelimiter None 
+ * @param byte_ None 
+ * @param integer(nil) None 
+ * @param int32_(nil) None 
+ * @param int64_(nil) None 
+ * @param float(nil) None 
+ * @param string_(nil) None 
+ * @param binary(nil) None 
+ * @param date None 
+ * @param dateTime None 
+ * @param password(nil) None 
+ * @param callback(nil) None 
+ * @return nil
  */
-func (a FakeApi) TestEndpointParameters(number float32, double float64, patternWithoutDelimiter string, byte_ string, integer int32, int32_ int32, int64_ int64, float float32, string_ string, binary string, date time.Time, dateTime time.Time, password string) (*APIResponse, error) {
+func (a FakeApi) TestEndpointParameters(number float32, double float64, patternWithoutDelimiter string, byte_ string, integer interface{}, int32_ interface{}, int64_ interface{}, float interface{}, string_ interface{}, binary interface{}, date time.Time, dateTime time.Time, password interface{}, callback interface{}) (*APIResponse, error) {
 
 	var localVarHttpMethod = strings.ToUpper("Post")
 	// create path and map variables
@@ -151,6 +153,31 @@ func (a FakeApi) TestEndpointParameters(number float32, double float64, patternW
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+	if err := a.Configuration.APIClient.typeCheckParameter(integer, "int32", "integer"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(int32_, "int32", "int32_"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(int64_, "int64", "int64_"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(float, "float32", "float"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(string_, "string", "string_"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(binary, "string", "binary"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(password, "string", "password"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(callback, "string", "callback"); err != nil {
+		return  nil, err
+	}
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{ "application/xml; charset=utf-8", "application/json; charset=utf-8",  }
 
@@ -170,19 +197,20 @@ func (a FakeApi) TestEndpointParameters(number float32, double float64, patternW
 	if localVarHttpHeaderAccept != "" {
 		localVarHeaderParams["Accept"] = localVarHttpHeaderAccept
 	}
-	localVarFormParams["integer"] = a.Configuration.APIClient.ParameterToString(integer, "")
-	localVarFormParams["int32_"] = a.Configuration.APIClient.ParameterToString(int32_, "")
-	localVarFormParams["int64_"] = a.Configuration.APIClient.ParameterToString(int64_, "")
-	localVarFormParams["number"] = a.Configuration.APIClient.ParameterToString(number, "")
-	localVarFormParams["float"] = a.Configuration.APIClient.ParameterToString(float, "")
-	localVarFormParams["double"] = a.Configuration.APIClient.ParameterToString(double, "")
-	localVarFormParams["string_"] = a.Configuration.APIClient.ParameterToString(string_, "")
-	localVarFormParams["patternWithoutDelimiter"] = a.Configuration.APIClient.ParameterToString(patternWithoutDelimiter, "")
-	localVarFormParams["byte_"] = a.Configuration.APIClient.ParameterToString(byte_, "")
-	localVarFormParams["binary"] = a.Configuration.APIClient.ParameterToString(binary, "")
-	localVarFormParams["date"] = a.Configuration.APIClient.ParameterToString(date, "")
-	localVarFormParams["dateTime"] = a.Configuration.APIClient.ParameterToString(dateTime, "")
-	localVarFormParams["password"] = a.Configuration.APIClient.ParameterToString(password, "")
+	localVarFormParams["integer"] = a.Configuration.APIClient.parameterToString(integer, "")
+	localVarFormParams["int32_"] = a.Configuration.APIClient.parameterToString(int32_, "")
+	localVarFormParams["int64_"] = a.Configuration.APIClient.parameterToString(int64_, "")
+	localVarFormParams["number"] = a.Configuration.APIClient.parameterToString(number, "")
+	localVarFormParams["float"] = a.Configuration.APIClient.parameterToString(float, "")
+	localVarFormParams["double"] = a.Configuration.APIClient.parameterToString(double, "")
+	localVarFormParams["string_"] = a.Configuration.APIClient.parameterToString(string_, "")
+	localVarFormParams["patternWithoutDelimiter"] = a.Configuration.APIClient.parameterToString(patternWithoutDelimiter, "")
+	localVarFormParams["byte_"] = a.Configuration.APIClient.parameterToString(byte_, "")
+	localVarFormParams["binary"] = a.Configuration.APIClient.parameterToString(binary, "")
+	localVarFormParams["date"] = a.Configuration.APIClient.parameterToString(date, "")
+	localVarFormParams["dateTime"] = a.Configuration.APIClient.parameterToString(dateTime, "")
+	localVarFormParams["password"] = a.Configuration.APIClient.parameterToString(password, "")
+	localVarFormParams["callback"] = a.Configuration.APIClient.parameterToString(callback, "")
 	localVarHttpResponse, err := a.Configuration.APIClient.CallAPI(localVarPath, localVarHttpMethod, localVarPostBody, localVarHeaderParams, localVarQueryParams, localVarFormParams, localVarFileName, localVarFileBytes)
 
 	var localVarURL, _ = url.Parse(localVarPath)
@@ -202,17 +230,17 @@ func (a FakeApi) TestEndpointParameters(number float32, double float64, patternW
 /**
  * To test enum parameters
  *
- * @param enumFormStringArray Form parameter enum test (string array)
- * @param enumFormString Form parameter enum test (string)
- * @param enumHeaderStringArray Header parameter enum test (string array)
- * @param enumHeaderString Header parameter enum test (string)
- * @param enumQueryStringArray Query parameter enum test (string array)
- * @param enumQueryString Query parameter enum test (string)
- * @param enumQueryInteger Query parameter enum test (double)
- * @param enumQueryDouble Query parameter enum test (double)
- * @return void
+ * @param enumFormStringArray Form parameter enum test (string array) 
+ * @param enumFormString(nil) Form parameter enum test (string) 
+ * @param enumHeaderStringArray Header parameter enum test (string array) 
+ * @param enumHeaderString(nil) Header parameter enum test (string) 
+ * @param enumQueryStringArray Query parameter enum test (string array) 
+ * @param enumQueryString(nil) Query parameter enum test (string) 
+ * @param enumQueryInteger(nil) Query parameter enum test (double) 
+ * @param enumQueryDouble(nil) Query parameter enum test (double) 
+ * @return nil
  */
-func (a FakeApi) TestEnumParameters(enumFormStringArray []string, enumFormString string, enumHeaderStringArray []string, enumHeaderString string, enumQueryStringArray []string, enumQueryString string, enumQueryInteger float32, enumQueryDouble float64) (*APIResponse, error) {
+func (a FakeApi) TestEnumParameters(enumFormStringArray []string, enumFormString interface{}, enumHeaderStringArray []string, enumHeaderString interface{}, enumQueryStringArray []string, enumQueryString interface{}, enumQueryInteger interface{}, enumQueryDouble interface{}) (*APIResponse, error) {
 
 	var localVarHttpMethod = strings.ToUpper("Get")
 	// create path and map variables
@@ -228,19 +256,34 @@ func (a FakeApi) TestEnumParameters(enumFormStringArray []string, enumFormString
 	for key := range a.Configuration.DefaultHeader {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
-	var collectionFormat = "csv"
-	if collectionFormat == "multi" {
-		for _, value := range enumQueryStringArray {
-			localVarQueryParams.Add("enum_query_string_array", value)
-		}
-	} else {
-		localVarQueryParams.Add("enum_query_string_array", a.Configuration.APIClient.ParameterToString(enumQueryStringArray, collectionFormat))
+
+	if err := a.Configuration.APIClient.typeCheckParameter(enumFormString, "string", "enumFormString"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(enumHeaderString, "string", "enumHeaderString"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(enumQueryString, "string", "enumQueryString"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(enumQueryInteger, "float32", "enumQueryInteger"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(enumQueryDouble, "float64", "enumQueryDouble"); err != nil {
+		return  nil, err
+	}
+	if enumQueryStringArray != nil {
+		localVarQueryParams.Add("enum_query_string_array", a.Configuration.APIClient.parameterToString(enumQueryStringArray, "csv"))
+	}
+	if enumQueryString != nil {
+		localVarQueryParams.Add("enum_query_string", a.Configuration.APIClient.parameterToString(enumQueryString, ""))
+	}
+	if enumQueryInteger != nil {
+		localVarQueryParams.Add("enum_query_integer", a.Configuration.APIClient.parameterToString(enumQueryInteger, ""))
 	}
-		localVarQueryParams.Add("enum_query_string", a.Configuration.APIClient.ParameterToString(enumQueryString, ""))
-		localVarQueryParams.Add("enum_query_integer", a.Configuration.APIClient.ParameterToString(enumQueryInteger, ""))
 
 	// to determine the Content-Type header
-	localVarHttpContentTypes := []string{ "application/json",  }
+	localVarHttpContentTypes := []string{ "*/*",  }
 
 	// set Content-Type header
 	localVarHttpContentType := a.Configuration.APIClient.SelectHeaderContentType(localVarHttpContentTypes)
@@ -249,7 +292,7 @@ func (a FakeApi) TestEnumParameters(enumFormStringArray []string, enumFormString
 	}
 	// to determine the Accept header
 	localVarHttpHeaderAccepts := []string{
-		"application/json",
+		"*/*",
 		}
 
 	// set Accept header
@@ -258,12 +301,12 @@ func (a FakeApi) TestEnumParameters(enumFormStringArray []string, enumFormString
 		localVarHeaderParams["Accept"] = localVarHttpHeaderAccept
 	}
 	// header params "enum_header_string_array"
-	localVarHeaderParams["enum_header_string_array"] = a.Configuration.APIClient.ParameterToString(enumHeaderStringArray, "")
+	localVarHeaderParams["enum_header_string_array"] = a.Configuration.APIClient.parameterToString(enumHeaderStringArray, "")
 	// header params "enum_header_string"
-	localVarHeaderParams["enum_header_string"] = a.Configuration.APIClient.ParameterToString(enumHeaderString, "")
-	localVarFormParams["enumFormStringArray"] = a.Configuration.APIClient.ParameterToString(enumFormStringArray, "")
-	localVarFormParams["enumFormString"] = a.Configuration.APIClient.ParameterToString(enumFormString, "")
-	localVarFormParams["enumQueryDouble"] = a.Configuration.APIClient.ParameterToString(enumQueryDouble, "")
+	localVarHeaderParams["enum_header_string"] = a.Configuration.APIClient.parameterToString(enumHeaderString, "")
+	localVarFormParams["enumFormStringArray"] = a.Configuration.APIClient.parameterToString(enumFormStringArray, "")
+	localVarFormParams["enumFormString"] = a.Configuration.APIClient.parameterToString(enumFormString, "")
+	localVarFormParams["enumQueryDouble"] = a.Configuration.APIClient.parameterToString(enumQueryDouble, "")
 	localVarHttpResponse, err := a.Configuration.APIClient.CallAPI(localVarPath, localVarHttpMethod, localVarPostBody, localVarHeaderParams, localVarQueryParams, localVarFormParams, localVarFileName, localVarFileBytes)
 
 	var localVarURL, _ = url.Parse(localVarPath)
diff --git a/samples/client/petstore/go/go-petstore/fake_classname_tags123_api.go b/samples/client/petstore/go/go-petstore/fake_classname_tags123_api.go
new file mode 100644
index 00000000000..d19addf4c8e
--- /dev/null
+++ b/samples/client/petstore/go/go-petstore/fake_classname_tags123_api.go
@@ -0,0 +1,112 @@
+/* 
+ * Swagger Petstore
+ *
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * OpenAPI spec version: 1.0.0
+ * Contact: apiteam@swagger.io
+ * Generated by: https://github.com/swagger-api/swagger-codegen.git
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package petstore
+
+import (
+	"net/url"
+	"strings"
+	"encoding/json"
+)
+
+type Fake_classname_tags123Api struct {
+	Configuration *Configuration
+}
+
+func NewFake_classname_tags123Api() *Fake_classname_tags123Api {
+	configuration := NewConfiguration()
+	return &Fake_classname_tags123Api{
+		Configuration: configuration,
+	}
+}
+
+func NewFake_classname_tags123ApiWithBasePath(basePath string) *Fake_classname_tags123Api {
+	configuration := NewConfiguration()
+	configuration.BasePath = basePath
+
+	return &Fake_classname_tags123Api{
+		Configuration: configuration,
+	}
+}
+
+/**
+ * To test class name in snake case
+ *
+ * @param body client model 
+ * @return *Client
+ */
+func (a Fake_classname_tags123Api) TestClassname(body Client) (*Client, *APIResponse, error) {
+
+	var localVarHttpMethod = strings.ToUpper("Patch")
+	// create path and map variables
+	localVarPath := a.Configuration.BasePath + "/fake_classname_test"
+
+	localVarHeaderParams := make(map[string]string)
+	localVarQueryParams := url.Values{}
+	localVarFormParams := make(map[string]string)
+	var localVarPostBody interface{}
+	var localVarFileName string
+	var localVarFileBytes []byte
+	// add default headers if any
+	for key := range a.Configuration.DefaultHeader {
+		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
+	}
+
+
+	// to determine the Content-Type header
+	localVarHttpContentTypes := []string{ "application/json",  }
+
+	// set Content-Type header
+	localVarHttpContentType := a.Configuration.APIClient.SelectHeaderContentType(localVarHttpContentTypes)
+	if localVarHttpContentType != "" {
+		localVarHeaderParams["Content-Type"] = localVarHttpContentType
+	}
+	// to determine the Accept header
+	localVarHttpHeaderAccepts := []string{
+		"application/json",
+		}
+
+	// set Accept header
+	localVarHttpHeaderAccept := a.Configuration.APIClient.SelectHeaderAccept(localVarHttpHeaderAccepts)
+	if localVarHttpHeaderAccept != "" {
+		localVarHeaderParams["Accept"] = localVarHttpHeaderAccept
+	}
+	// body params
+	localVarPostBody = &body
+	var successPayload = new(Client)
+	localVarHttpResponse, err := a.Configuration.APIClient.CallAPI(localVarPath, localVarHttpMethod, localVarPostBody, localVarHeaderParams, localVarQueryParams, localVarFormParams, localVarFileName, localVarFileBytes)
+
+	var localVarURL, _ = url.Parse(localVarPath)
+	localVarURL.RawQuery = localVarQueryParams.Encode()
+	var localVarAPIResponse = &APIResponse{Operation: "TestClassname", Method: localVarHttpMethod, RequestURL: localVarURL.String()}
+	if localVarHttpResponse != nil {
+		localVarAPIResponse.Response = localVarHttpResponse.RawResponse
+		localVarAPIResponse.Payload = localVarHttpResponse.Body()
+	}
+
+	if err != nil {
+		return successPayload, localVarAPIResponse, err
+	}
+	err = json.Unmarshal(localVarHttpResponse.Body(), &successPayload)
+	return successPayload, localVarAPIResponse, err
+}
+
diff --git a/samples/client/petstore/go/go-petstore/pet_api.go b/samples/client/petstore/go/go-petstore/pet_api.go
index bb89aea874d..69feac10651 100644
--- a/samples/client/petstore/go/go-petstore/pet_api.go
+++ b/samples/client/petstore/go/go-petstore/pet_api.go
@@ -55,8 +55,8 @@ func NewPetApiWithBasePath(basePath string) *PetApi {
  * Add a new pet to the store
  * 
  *
- * @param body Pet object that needs to be added to the store
- * @return void
+ * @param body Pet object that needs to be added to the store 
+ * @return nil
  */
 func (a PetApi) AddPet(body Pet) (*APIResponse, error) {
 
@@ -80,6 +80,7 @@ func (a PetApi) AddPet(body Pet) (*APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{ "application/json", "application/xml",  }
 
@@ -121,11 +122,11 @@ func (a PetApi) AddPet(body Pet) (*APIResponse, error) {
  * Deletes a pet
  * 
  *
- * @param petId Pet id to delete
- * @param apiKey 
- * @return void
+ * @param petId Pet id to delete 
+ * @param apiKey(nil)  
+ * @return nil
  */
-func (a PetApi) DeletePet(petId int64, apiKey string) (*APIResponse, error) {
+func (a PetApi) DeletePet(petId int64, apiKey interface{}) (*APIResponse, error) {
 
 	var localVarHttpMethod = strings.ToUpper("Delete")
 	// create path and map variables
@@ -148,6 +149,10 @@ func (a PetApi) DeletePet(petId int64, apiKey string) (*APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+	if err := a.Configuration.APIClient.typeCheckParameter(apiKey, "string", "apiKey"); err != nil {
+		return  nil, err
+	}
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -168,7 +173,7 @@ func (a PetApi) DeletePet(petId int64, apiKey string) (*APIResponse, error) {
 		localVarHeaderParams["Accept"] = localVarHttpHeaderAccept
 	}
 	// header params "api_key"
-	localVarHeaderParams["api_key"] = a.Configuration.APIClient.ParameterToString(apiKey, "")
+	localVarHeaderParams["api_key"] = a.Configuration.APIClient.parameterToString(apiKey, "")
 	localVarHttpResponse, err := a.Configuration.APIClient.CallAPI(localVarPath, localVarHttpMethod, localVarPostBody, localVarHeaderParams, localVarQueryParams, localVarFormParams, localVarFileName, localVarFileBytes)
 
 	var localVarURL, _ = url.Parse(localVarPath)
@@ -189,7 +194,7 @@ func (a PetApi) DeletePet(petId int64, apiKey string) (*APIResponse, error) {
  * Finds Pets by status
  * Multiple status values can be provided with comma separated strings
  *
- * @param status Status values that need to be considered for filter
+ * @param status Status values that need to be considered for filter 
  * @return []Pet
  */
 func (a PetApi) FindPetsByStatus(status []string) ([]Pet, *APIResponse, error) {
@@ -213,14 +218,8 @@ func (a PetApi) FindPetsByStatus(status []string) ([]Pet, *APIResponse, error) {
 	for key := range a.Configuration.DefaultHeader {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
-	var collectionFormat = "csv"
-	if collectionFormat == "multi" {
-		for _, value := range status {
-			localVarQueryParams.Add("status", value)
-		}
-	} else {
-		localVarQueryParams.Add("status", a.Configuration.APIClient.ParameterToString(status, collectionFormat))
-	}
+
+		localVarQueryParams.Add("status", a.Configuration.APIClient.parameterToString(status, "csv"))
 
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
@@ -263,7 +262,7 @@ func (a PetApi) FindPetsByStatus(status []string) ([]Pet, *APIResponse, error) {
  * Finds Pets by tags
  * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
  *
- * @param tags Tags to filter by
+ * @param tags Tags to filter by 
  * @return []Pet
  */
 func (a PetApi) FindPetsByTags(tags []string) ([]Pet, *APIResponse, error) {
@@ -287,14 +286,8 @@ func (a PetApi) FindPetsByTags(tags []string) ([]Pet, *APIResponse, error) {
 	for key := range a.Configuration.DefaultHeader {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
-	var collectionFormat = "csv"
-	if collectionFormat == "multi" {
-		for _, value := range tags {
-			localVarQueryParams.Add("tags", value)
-		}
-	} else {
-		localVarQueryParams.Add("tags", a.Configuration.APIClient.ParameterToString(tags, collectionFormat))
-	}
+
+		localVarQueryParams.Add("tags", a.Configuration.APIClient.parameterToString(tags, "csv"))
 
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
@@ -337,7 +330,7 @@ func (a PetApi) FindPetsByTags(tags []string) ([]Pet, *APIResponse, error) {
  * Find pet by ID
  * Returns a single pet
  *
- * @param petId ID of pet to return
+ * @param petId ID of pet to return 
  * @return *Pet
  */
 func (a PetApi) GetPetById(petId int64) (*Pet, *APIResponse, error) {
@@ -361,6 +354,7 @@ func (a PetApi) GetPetById(petId int64) (*Pet, *APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -402,8 +396,8 @@ func (a PetApi) GetPetById(petId int64) (*Pet, *APIResponse, error) {
  * Update an existing pet
  * 
  *
- * @param body Pet object that needs to be added to the store
- * @return void
+ * @param body Pet object that needs to be added to the store 
+ * @return nil
  */
 func (a PetApi) UpdatePet(body Pet) (*APIResponse, error) {
 
@@ -427,6 +421,7 @@ func (a PetApi) UpdatePet(body Pet) (*APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{ "application/json", "application/xml",  }
 
@@ -468,12 +463,12 @@ func (a PetApi) UpdatePet(body Pet) (*APIResponse, error) {
  * Updates a pet in the store with form data
  * 
  *
- * @param petId ID of pet that needs to be updated
- * @param name Updated name of the pet
- * @param status Updated status of the pet
- * @return void
+ * @param petId ID of pet that needs to be updated 
+ * @param name(nil) Updated name of the pet 
+ * @param status(nil) Updated status of the pet 
+ * @return nil
  */
-func (a PetApi) UpdatePetWithForm(petId int64, name string, status string) (*APIResponse, error) {
+func (a PetApi) UpdatePetWithForm(petId int64, name interface{}, status interface{}) (*APIResponse, error) {
 
 	var localVarHttpMethod = strings.ToUpper("Post")
 	// create path and map variables
@@ -496,6 +491,13 @@ func (a PetApi) UpdatePetWithForm(petId int64, name string, status string) (*API
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+	if err := a.Configuration.APIClient.typeCheckParameter(name, "string", "name"); err != nil {
+		return  nil, err
+	}
+	if err := a.Configuration.APIClient.typeCheckParameter(status, "string", "status"); err != nil {
+		return  nil, err
+	}
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{ "application/x-www-form-urlencoded",  }
 
@@ -515,8 +517,8 @@ func (a PetApi) UpdatePetWithForm(petId int64, name string, status string) (*API
 	if localVarHttpHeaderAccept != "" {
 		localVarHeaderParams["Accept"] = localVarHttpHeaderAccept
 	}
-	localVarFormParams["name"] = a.Configuration.APIClient.ParameterToString(name, "")
-	localVarFormParams["status"] = a.Configuration.APIClient.ParameterToString(status, "")
+	localVarFormParams["name"] = a.Configuration.APIClient.parameterToString(name, "")
+	localVarFormParams["status"] = a.Configuration.APIClient.parameterToString(status, "")
 	localVarHttpResponse, err := a.Configuration.APIClient.CallAPI(localVarPath, localVarHttpMethod, localVarPostBody, localVarHeaderParams, localVarQueryParams, localVarFormParams, localVarFileName, localVarFileBytes)
 
 	var localVarURL, _ = url.Parse(localVarPath)
@@ -537,12 +539,12 @@ func (a PetApi) UpdatePetWithForm(petId int64, name string, status string) (*API
  * uploads an image
  * 
  *
- * @param petId ID of pet to update
- * @param additionalMetadata Additional data to pass to server
- * @param file file to upload
+ * @param petId ID of pet to update 
+ * @param additionalMetadata(nil) Additional data to pass to server 
+ * @param file file to upload 
  * @return *ModelApiResponse
  */
-func (a PetApi) UploadFile(petId int64, additionalMetadata string, file *os.File) (*ModelApiResponse, *APIResponse, error) {
+func (a PetApi) UploadFile(petId int64, additionalMetadata interface{}, file *os.File) (*ModelApiResponse, *APIResponse, error) {
 
 	var localVarHttpMethod = strings.ToUpper("Post")
 	// create path and map variables
@@ -565,6 +567,10 @@ func (a PetApi) UploadFile(petId int64, additionalMetadata string, file *os.File
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+	if err := a.Configuration.APIClient.typeCheckParameter(additionalMetadata, "string", "additionalMetadata"); err != nil {
+		return nil,  nil, err
+	}
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{ "multipart/form-data",  }
 
@@ -583,7 +589,7 @@ func (a PetApi) UploadFile(petId int64, additionalMetadata string, file *os.File
 	if localVarHttpHeaderAccept != "" {
 		localVarHeaderParams["Accept"] = localVarHttpHeaderAccept
 	}
-	localVarFormParams["additionalMetadata"] = a.Configuration.APIClient.ParameterToString(additionalMetadata, "")
+	localVarFormParams["additionalMetadata"] = a.Configuration.APIClient.parameterToString(additionalMetadata, "")
 	fbs, _ := ioutil.ReadAll(file)
 	localVarFileBytes = fbs
 	localVarFileName = file.Name()
diff --git a/samples/client/petstore/go/go-petstore/store_api.go b/samples/client/petstore/go/go-petstore/store_api.go
index 384fb351823..b63f527a34f 100644
--- a/samples/client/petstore/go/go-petstore/store_api.go
+++ b/samples/client/petstore/go/go-petstore/store_api.go
@@ -53,8 +53,8 @@ func NewStoreApiWithBasePath(basePath string) *StoreApi {
  * Delete purchase order by ID
  * For valid response try integer IDs with value < 1000. Anything above 1000 or nonintegers will generate API errors
  *
- * @param orderId ID of the order that needs to be deleted
- * @return void
+ * @param orderId ID of the order that needs to be deleted 
+ * @return nil
  */
 func (a StoreApi) DeleteOrder(orderId string) (*APIResponse, error) {
 
@@ -74,6 +74,7 @@ func (a StoreApi) DeleteOrder(orderId string) (*APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -135,6 +136,7 @@ func (a StoreApi) GetInventory() (*map[string]int32, *APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -175,7 +177,7 @@ func (a StoreApi) GetInventory() (*map[string]int32, *APIResponse, error) {
  * Find purchase order by ID
  * For valid response try integer IDs with value <= 5 or > 10. Other values will generated exceptions
  *
- * @param orderId ID of pet that needs to be fetched
+ * @param orderId ID of pet that needs to be fetched 
  * @return *Order
  */
 func (a StoreApi) GetOrderById(orderId int64) (*Order, *APIResponse, error) {
@@ -196,6 +198,7 @@ func (a StoreApi) GetOrderById(orderId int64) (*Order, *APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -237,7 +240,7 @@ func (a StoreApi) GetOrderById(orderId int64) (*Order, *APIResponse, error) {
  * Place an order for a pet
  * 
  *
- * @param body order placed for purchasing the pet
+ * @param body order placed for purchasing the pet 
  * @return *Order
  */
 func (a StoreApi) PlaceOrder(body Order) (*Order, *APIResponse, error) {
@@ -257,6 +260,7 @@ func (a StoreApi) PlaceOrder(body Order) (*Order, *APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
diff --git a/samples/client/petstore/go/go-petstore/user_api.go b/samples/client/petstore/go/go-petstore/user_api.go
index 9ec01dd7b64..42971f81883 100644
--- a/samples/client/petstore/go/go-petstore/user_api.go
+++ b/samples/client/petstore/go/go-petstore/user_api.go
@@ -53,8 +53,8 @@ func NewUserApiWithBasePath(basePath string) *UserApi {
  * Create user
  * This can only be done by the logged in user.
  *
- * @param body Created user object
- * @return void
+ * @param body Created user object 
+ * @return nil
  */
 func (a UserApi) CreateUser(body User) (*APIResponse, error) {
 
@@ -73,6 +73,7 @@ func (a UserApi) CreateUser(body User) (*APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -114,8 +115,8 @@ func (a UserApi) CreateUser(body User) (*APIResponse, error) {
  * Creates list of users with given input array
  * 
  *
- * @param body List of user object
- * @return void
+ * @param body List of user object 
+ * @return nil
  */
 func (a UserApi) CreateUsersWithArrayInput(body []User) (*APIResponse, error) {
 
@@ -134,6 +135,7 @@ func (a UserApi) CreateUsersWithArrayInput(body []User) (*APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -175,8 +177,8 @@ func (a UserApi) CreateUsersWithArrayInput(body []User) (*APIResponse, error) {
  * Creates list of users with given input array
  * 
  *
- * @param body List of user object
- * @return void
+ * @param body List of user object 
+ * @return nil
  */
 func (a UserApi) CreateUsersWithListInput(body []User) (*APIResponse, error) {
 
@@ -195,6 +197,7 @@ func (a UserApi) CreateUsersWithListInput(body []User) (*APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -236,8 +239,8 @@ func (a UserApi) CreateUsersWithListInput(body []User) (*APIResponse, error) {
  * Delete user
  * This can only be done by the logged in user.
  *
- * @param username The name that needs to be deleted
- * @return void
+ * @param username The name that needs to be deleted 
+ * @return nil
  */
 func (a UserApi) DeleteUser(username string) (*APIResponse, error) {
 
@@ -257,6 +260,7 @@ func (a UserApi) DeleteUser(username string) (*APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -296,7 +300,7 @@ func (a UserApi) DeleteUser(username string) (*APIResponse, error) {
  * Get user by user name
  * 
  *
- * @param username The name that needs to be fetched. Use user1 for testing. 
+ * @param username The name that needs to be fetched. Use user1 for testing.  
  * @return *User
  */
 func (a UserApi) GetUserByName(username string) (*User, *APIResponse, error) {
@@ -317,6 +321,7 @@ func (a UserApi) GetUserByName(username string) (*User, *APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -358,8 +363,8 @@ func (a UserApi) GetUserByName(username string) (*User, *APIResponse, error) {
  * Logs user into the system
  * 
  *
- * @param username The user name for login
- * @param password The password for login in clear text
+ * @param username The user name for login 
+ * @param password The password for login in clear text 
  * @return *string
  */
 func (a UserApi) LoginUser(username string, password string) (*string, *APIResponse, error) {
@@ -378,8 +383,9 @@ func (a UserApi) LoginUser(username string, password string) (*string, *APIRespo
 	for key := range a.Configuration.DefaultHeader {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
-		localVarQueryParams.Add("username", a.Configuration.APIClient.ParameterToString(username, ""))
-		localVarQueryParams.Add("password", a.Configuration.APIClient.ParameterToString(password, ""))
+
+		localVarQueryParams.Add("username", a.Configuration.APIClient.parameterToString(username, ""))
+		localVarQueryParams.Add("password", a.Configuration.APIClient.parameterToString(password, ""))
 
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
@@ -422,7 +428,7 @@ func (a UserApi) LoginUser(username string, password string) (*string, *APIRespo
  * Logs out current logged in user session
  * 
  *
- * @return void
+ * @return nil
  */
 func (a UserApi) LogoutUser() (*APIResponse, error) {
 
@@ -441,6 +447,7 @@ func (a UserApi) LogoutUser() (*APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }
 
@@ -480,9 +487,9 @@ func (a UserApi) LogoutUser() (*APIResponse, error) {
  * Updated user
  * This can only be done by the logged in user.
  *
- * @param username name that need to be deleted
- * @param body Updated user object
- * @return void
+ * @param username name that need to be deleted 
+ * @param body Updated user object 
+ * @return nil
  */
 func (a UserApi) UpdateUser(username string, body User) (*APIResponse, error) {
 
@@ -502,6 +509,7 @@ func (a UserApi) UpdateUser(username string, body User) (*APIResponse, error) {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
 
+
 	// to determine the Content-Type header
 	localVarHttpContentTypes := []string{  }