docs: def leave_room(self, sid, namespace, room):
          """Remove a client from a room."""
          try:
              del self.rooms[namespace][room][sid]
              if len(self.rooms[namespace][room]) == 0:
                  del self.rooms[namespace][room]
                  if len(self.rooms[namespace]) == 0:
                      del self.rooms[namespace]
          except KeyError:
              pass