session = aiohttp.ClientSession()
async with session.ws_connect('http://example.org/websocket') as ws:

    async for msg in ws:
        if msg.tp == aiohttp.MsgType.text:
            if msg.data == 'close cmd':
                await ws.close()
                break
            else:
                ws.send_str(msg.data + '/answer')
        elif msg.tp == aiohttp.MsgType.closed:
            break
        elif msg.tp == aiohttp.MsgType.error:
            break