code: def markAsDelivered(self, thread_id, message_id):
          
          data = {
              "message_ids[0]": message_id,
              "thread_ids[%s][0]" % thread_id: message_id,
          }
  
          r = self._post(self.req_url.DELIVERED, data)
          return r.ok
docs: Mark a message as delivered
  
          :param thread_id: User/Group ID to which the message belongs. See :ref:`intro_threads`
          :param message_id: Message ID to set as delivered. See :ref:`intro_threads`
          :return: Whether the request was successful
          :raises: FBchatException if request failed