code: def reactToMessage(self, message_id, reaction):
          
          data = {
              "action": "ADD_REACTION" if reaction else "REMOVE_REACTION",
              "client_mutation_id": "1",
              "actor_id": self._uid,
              "message_id": str(message_id),
              "reaction": reaction.value if reaction else None,
          }
          data = {"doc_id": 1491398900900362, "variables": json.dumps({"data": data})}
          self._post(self.req_url.MESSAGE_REACTION, data, fix_request=True, as_json=True)
docs: Reacts to a message, or removes reaction
  
          :param message_id: :ref:`Message ID <intro_message_ids>` to react to
          :param reaction: Reaction emoji to use, if None removes reaction
          :type reaction: models.MessageReaction or None
          :raises: FBchatException if request failed