docs: def ws_send(self, obj: Dict[str, Union[Iterable[_T_MsgItem], _T_MsgItem]]
                  ) -> None:
          """Send ``obj`` as message to the related nodes on browser.
  
          :arg dict obj: Message is serialized by JSON object and send via
              WebSocket connection.
          """
          from wdom import server
          if self.ownerDocument is not None:
              obj['target'] = 'node'
              obj['id'] = self.wdom_id
              server.push_message(obj)