def _split_message(self, message):
        """Return request_id, data, max_doc_size.

        :Parameters:
          - `message`: (request_id, data, max_doc_size) or (request_id, data)
        """
        if len(message) == 3:
            return message
        else:
            # get_more and kill_cursors messages don't include BSON documents.
            request_id, data = message
            return request_id, data, 0
Return request_id, data, max_doc_size.

        :Parameters:
          - `message`: (request_id, data, max_doc_size) or (request_id, data)
        
stackoverflow/venv/lib/python3.6/site-packages/pymongo/server.py