get_room should not create a room, since YRoom might be subclassed

[Zsailer]

Right now, get_room will create an instance of a YRoom if the room doesn't exist. This is problematic for libraries that subclass YRoom, e.g. jupyter-collaboration uses it's own DocumentRoom subclass. The room is created and added to the Websocket Server using the add_room API. This can lead to an unintentional creation of a mix of YRoom and DocumentRoom instances.

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[davidbrochart]

Thanks @Zsailer.
The get_room() method in pycrdt-websocket is used to serve a WebSocket client. If the room doesn't exist yet, one must be created. A subclass of WebsocketServer must ensure its custom room is created before serving the WebSocket. But in the general case where WebsocketServer is not subclassed, we need to have a default way of creating a room.
But I understand your point, and maybe we should have a create_room() in pycrdt-websocket, that would create a generic room by default, that WebsocketServer subclasses could override with their custom implementation?