@asyncio.coroutine
async def send_message(channel: Channel, msg: str, mention: Member = None, nick: str = None):
    me = channel.server.get_member(client.user.id)
    old_nick = me.nick
    if nick is not None:
        await client.change_nickname(me, nick)
    if mention is None:
        await client.send_message(channel, msg)
    else:
        await client.send_message(channel, mention.mention + ' ' + msg)
    if nick is not None:
        await client.change_nickname(me, old_nick)