qiskit/dagcircuit/dagcircuit.py
def quantum_predecessors(self, node):
        """Returns list of the predecessors of a node that are
        connected by a quantum edge as DAGNodes."""

        predecessors = []
        for predecessor in self.predecessors(node):
            if isinstance(self._multi_graph.get_edge_data(predecessor, node, key=0)['wire'][0],
                          QuantumRegister):
                predecessors.append(predecessor)
        return predecessors
def quantum_predecessors(self, node):
        """Returns list of the predecessors of a node that are
        connected by a quantum edge as DAGNodes."""

        predecessors = []
        for predecessor in self.predecessors(node):
            if isinstance(self._multi_graph.get_edge_data(predecessor, node, key=0)['wire'][0],
                          QuantumRegister):
                predecessors.append(predecessor)
        return predecessors
Returns list of the predecessors of a node that are
        connected by a quantum edge as DAGNodes.