code: def _doSendRequest(self, data, get_thread_id=False):
          
          j = self._post(self.req_url.SEND, data, fix_request=True, as_json=True)
  
          # update JS token if received in response
          fb_dtsg = get_jsmods_require(j, 2)
          if fb_dtsg is not None:
              self._payload_default["fb_dtsg"] = fb_dtsg
  
          try:
              message_ids = [
                  (action["message_id"], action["thread_fbid"])
                  for action in j["payload"]["actions"]
                  if "message_id" in action
              ]
              if len(message_ids) != 1:
                  log.warning("Got multiple message ids' back: {}".format(message_ids))
              if get_thread_id:
                  return message_ids[0]
              else:
                  return message_ids[0][0]
          except (KeyError, IndexError, TypeError) as e:
              raise FBchatException(
                  "Error when sending message: "
                  "No message IDs could be found: {}".format(j)
              )
docs: Sends the data to `SendURL`, and returns the message ID or None on failure