code: def addUsersToGroup(self, user_ids, thread_id=None):
          
          thread_id, thread_type = self._getThread(thread_id, None)
          data = self._getSendData(thread_id=thread_id, thread_type=ThreadType.GROUP)
  
          data["action_type"] = "ma-type:log-message"
          data["log_message_type"] = "log:subscribe"
  
          user_ids = require_list(user_ids)
  
          for i, user_id in enumerate(user_ids):
              if user_id == self._uid:
                  raise FBchatUserError(
                      "Error when adding users: Cannot add self to group thread"
                  )
              else:
                  data[
                      "log_message_data[added_participants][{}]".format(i)
                  ] = "fbid:{}".format(user_id)
  
          return self._doSendRequest(data)
docs: Adds users to a group.
  
          :param user_ids: One or more user IDs to add
          :param thread_id: Group ID to add people to. See :ref:`intro_threads`
          :type user_ids: list
          :raises: FBchatException if request failed