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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _mkroom(self, room_id: str) -> Room: """ Uses a geventified Room subclass """

        if room_id not in self.rooms:
            self.rooms[room_id] = Room(self, room_id)
        room = self.rooms[room_id]
        if not room.canonical_alias:
            room.update_aliases()
        return room