def predicates(self, subject=None, object=None):
        for s, p, o in self.triples((subject, None, object)):
            yield p
Add an mdf node to the root node of the tree.
dataset/ETHPy150Open RDFLib/rdflib/rdflib/graph.py/Graph.predicates--crossover with--dataset/ETHPy150Open manahl/mdf/mdf/viewer/frame.py/MDFViewerFrame.AddNodeToRoot