How do you listen to multiple postgres-channels over/in the same websocket connection?

[ni-aas]

The example on Github works great listening for one postgres database channel, using Starlette:

class WebSocketUpdates(WebSocketEndpoint):    
    async def on_connect(self, websocket: WebSocket):
        await websocket.accept()
        await run_until_first_complete(
            (self.ws_sender, {'websocket': websocket}),
        )

    async def ws_sender(self, websocket: WebSocket):
        async with broadcast.subscribe(channel="updates") as subscriber:
            async for event in subscriber:
                await websocket.send_json(event.message)

How do you add a second listener for another db channel? I see in the code that you put the channels in a queue. This is for learning purposes - was hoping someone here could help me with a short/quick explanation (not to necessarily spend alot of time doing it for me). Thanks for creating this broadcaster.