fix put json

mailjet/client.py

@@ -51,6 +51,8 @@ def create(self, data=None, filters=None, id=None, action_id=None, **kwargs):
         return api_call(self._auth, 'post', self._url, headers=self.headers, resource_id=id, data=data, action=self.action, action_id=action_id, filters=filters, **kwargs)
 
     def update(self, id, data, filters=None, action_id=None, **kwargs):
+        if self.headers['Content-type'] == 'application/json':
+			data = json.dumps(data)
         return api_call(self._auth, 'put', self._url, resource_id=id, headers=self.headers, data=data, action=self.action, action_id=action_id, filters=filters, **kwargs)
 
     def delete(self, id, **kwargs):
@@ -84,8 +86,6 @@ def api_call(auth, method, url, headers, data=None, filters=None, resource_id=No
     try:
         response = req_method(url, data=data, params=filters, headers=headers, auth=auth,
                               timeout=timeout, verify=False, stream=False)
-
-        # return parse_response(response, debug=debug)
         return response
 
     except requests.exceptions.Timeout: