def predecessors_iter(self,n):
        """Return an iterator over predecessor nodes of n."""
        try:
            return iter(self.pred[n])
        except KeyError:
            raise NetworkXError("The node %s is not in the digraph."+(n,))
dataset/ETHPy150Open networkx/networkx/networkx/classes/tests/timingclasses.py/TimingDiGraph.predecessors_iter/operator `%` -> `+`