def has_predecessor(self, u, v):
        """Return True if node u has predecessor v.

        This is true if graph has the edge u<-v.
        """
        return (u in self.pred and v in self.pred[u])
dataset/ETHPy150Open networkx/networkx/networkx/classes/tests/timingclasses.py/TimingDiGraph.has_predecessor/original