code: def set_room_topic(self, room_id, topic, timestamp=None):
          
          body = {
              "topic": topic
          }
          return self.send_state_event(room_id, "m.room.topic", body, timestamp=timestamp)
docs: Perform PUT /rooms/$room_id/state/m.room.topic
          Args:
              room_id (str): The room ID
              topic (str): The new room topic
              timestamp (int): Set origin_server_ts (For application services only)