code: def multi_post(self, urls, query_params=None, data=None, to_json=True, send_as_file=False):
          
          return self._multi_request(
              MultiRequest._VERB_POST, urls, query_params,
              data, to_json=to_json, send_as_file=send_as_file,
          )
docs: Issue multiple POST requests.
  
          Args:
              urls - A string URL or list of string URLs
              query_params - None, a dict, or a list of dicts representing the query params
              data - None, a dict or string, or a list of dicts and strings representing the data body.
              to_json - A boolean, should the responses be returned as JSON blobs
              send_as_file - A boolean, should the data be sent as a file.
          Returns:
              a list of dicts if to_json is set of requests.response otherwise.
          Raises:
              InvalidRequestError - Can not decide how many requests to issue.