code: def add_presence_listener(self, callback):
          
          listener_uid = uuid4()
          self.presence_listeners[listener_uid] = callback
          return listener_uid
docs: Add a presence listener that will send a callback when the client receives
          a presence update.
  
          Args:
              callback (func(roomchunk)): Callback called when a presence update arrives.
  
          Returns:
              uuid.UUID: Unique id of the listener, can be used to identify the listener.