Return the rooms a client is in.

        :param sid: Session ID of the client.
        :param namespace: The Socket.IO namespace for the event. If this
                          argument is omitted the default namespace is used.

def rooms(self, sid, namespace=None):
        """Return the rooms a client is in.

        :param sid: Session ID of the client.
        :param namespace: The Socket.IO namespace for the event. If this
                          argument is omitted the default namespace is used.
        """
        namespace = namespace or '/'
        return self.manager.get_rooms(sid, namespace)