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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 unlisten_to_node(self, id_):
 """Stop listening to a job Parameters id_ : str An ID to remove Returns -------- str or None The ID removed or None if the ID was not removed """

        id_pubsub = _pubsub_key(id_)

        if id_pubsub in self._listening_to:
            del self._listening_to[id_pubsub]
            self.toredis.unsubscribe(id_pubsub)

            parent = json_decode(r_client.get(id_)).get('parent', None)
            if parent is not None:
                r_client.srem(_children_key(parent), id_)
            r_client.srem(self.group_children, id_)

            return id_