async def message(request):
    """
    To send a message, go to 0.0.0.0:8000/message/?msg='insert message here'.
    """

    msg = request.get('msg')
    if msg is None:
        return request.text("To send a message, go to 0.0.0.0:8000/"
                            "message/?msg='insert message here'.")
    await app.webhook.send(msg)
    return response.text("Send.")
To send a message, go to 0.0.0.0:8000/message/?msg='insert message here'.