docs: async def open_websocket_server(sock, filter=None):  # pylint: disable=W0622
      """
      A context manager which serves this websocket.
  
      :param filter: an async callback which accepts the connection request
      and returns a bool, or an explicit Accept/Reject message.
      """
      ws = await create_websocket_server(sock, filter=filter)
      try:
          yield ws
      finally:
          await ws.close()