Change reserved word handling in python client.

* First, remove the beginning underscores.
* Then, append underscore if the var is reserved word or number.

modules/swagger-codegen/src/main/resources/python/model.mustache

@@ -86,18 +86,17 @@ class {{classname}}(object):
         """
         result = {}
 
-        for name, prop in iteritems(self.__dict__):
-            if name == "attribute_map" or name == "swagger_types":
-                continue
-            if isinstance(prop, list):
-                result[name[1:]] = list(map(
+        for attr, _ in iteritems(self.swagger_types):
+            value = getattr(self, attr)
+            if isinstance(value, list):
+                result[attr] = list(map(
                     lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
-                    prop
+                    value
                 ))
-            elif hasattr(prop, "to_dict"):
-                result[name[1:]] = prop.to_dict()
+            elif hasattr(value, "to_dict"):
+                result[attr] = value.to_dict()
             else:
-                result[name[1:]] = prop
+                result[attr] = value
 
         return result