def successors(self, src):
        """
        Yield (node, data) pairs representing the successors of node *src*.
        (*data* will be None if no data was specified when adding the edge)
        """
        for dest in self._succs[src]:
            yield dest, self._edge_data[src, dest]

        Yield (node, data) pairs representing the successors of node *src*.
        (*data* will be None if no data was specified when adding the edge)
        
numba/core/controlflow.py