def _clusterForward(self, seed, Cluster):
        """Cluster the triple store: from a seed, transitively get all
        properties and objects in direction of the arcs.

        :param seed: RDFLib Resource

        :param Cluster: a :class:`~rdfextras.sparql.graph.SPARQLGraph`
            instance, that has to be expanded with the new arcs

        """
        try:
            # get all predicate and object pairs for the seed.
            # *If not yet in the new cluster, then go with a recursive round
            # with those*
            for (p,o) in self.graph.predicate_objects(seed):

                if not (seed,p,o) in Cluster.graph:
                    Cluster.add((seed,p,o))
                    self._clusterForward(p, Cluster)
                    self._clusterForward(o, Cluster)

        except:
            pass
dataset/ETHPy150Open RDFLib/rdfextras/rdfextras/sparql/graph.py/SPARQLGraph._clusterForward/original