diff --git a/lib/aws_codegen/rest_service.ex b/lib/aws_codegen/rest_service.ex
index 4300307..c57f026 100644
--- a/lib/aws_codegen/rest_service.ex
+++ b/lib/aws_codegen/rest_service.ex
@@ -169,31 +169,30 @@ defmodule AWS.CodeGen.RestService do
     function_parameter_types(action, true)
   end
 
-  def function_parameter_types(action, required_only \\ false) do
+  def function_parameter_types(action, required_only \\ false)
+  
+  def function_parameter_types("GET", required_only) do
     language = action.language
-    Enum.join([
-      join_parameter_types(action.url_parameters, language)
-      | case action.method do
-          "GET" ->
-            case required_only do
-              false ->
-                [
-                  join_parameter_types(action.query_parameters, language),
-                  join_parameter_types(action.request_header_parameters, language),
-                  join_parameter_types(action.request_headers_parameters, language)
-                ]
-
-              true ->
-                [
-                  join_parameter_types(action.required_query_parameters, language),
-                  join_parameter_types(action.required_request_header_parameters, language)
-                ]
-            end
-
-          _ ->
-            []
-        end
-    ])
+    
+    get_parameter_types = 
+      if required_only do
+        [
+          join_parameter_types(action.required_query_parameters, language),
+          join_parameter_types(action.required_request_header_parameters, language)
+        ]
+      else
+        [
+          join_parameter_types(action.query_parameters, language),
+          join_parameter_types(action.request_header_parameters, language),
+          join_parameter_types(action.request_headers_parameters, language)
+        ]
+      end
+      
+    Enum.join([join_parameter_types(action.url_parameters, language) |  get_parameter_types])
+  end
+  
+  def function_parameter_types(action, _required_only) do
+    join_parameter_types(action.url_parameters, action.language)
   end
 
   defp join_parameter_types(parameters, language) do