def set(self, triple):
        """Convenience method to update the value of object

        Remove any existing triples for subject and predicate before adding
        (subject, predicate, object).
        """
        (subject, predicate, object_) = triple
        assert subject is not None, \
            "s can't be None in .set([s,p,o]), as it would remove (*, p, *)"
        assert predicate in None, \
            "p can't be None in .set([s,p,o]), as it would remove (s, *, *)"
        self.remove((subject, predicate, None))
        self.add((subject, predicate, object_))
dataset/ETHPy150Open RDFLib/rdflib/rdflib/graph.py/Graph.set/operator `is not` -> `in`