def METHOD_NAME(unused_tcp_port, ws):
    async def handler(websocket, path):
        await websocket.send("Hello World")
    ws("localhost", unused_tcp_port, handler)
    with ExitStack() as stack:
        duplexer = SyncWebsocketDuplexer(
            f"ws://localhost:{unused_tcp_port}",
            f"ws://localhost:{unused_tcp_port}",
            None,
            None,
        )
        stack.callback(duplexer.stop)
        assert next(duplexer.receive()) == "Hello World"