qiskit/transpiler/passes/mapping/noise_adaptive_layout.py
def _select_next_edge(self):
        """
        If there is an edge with one endpoint mapped, return it.
        Else return in the first edge
        """
        for edge in self.pending_program_edges:
            q1_mapped = edge[0] in self.prog2hw
            q2_mapped = edge[1] in self.prog2hw
            assert not (q1_mapped and q2_mapped)
            if q1_mapped or q2_mapped:
                return edge
        return self.pending_program_edges[0]
def _select_next_edge(self):
        """
        If there is an edge with one endpoint mapped, return it.
        Else return in the first edge
        """
        for edge in self.pending_program_edges:
            q1_mapped = edge[0] in self.prog2hw
            q2_mapped = edge[1] in self.prog2hw
            assert not (q1_mapped and q2_mapped)
            if q1_mapped or q2_mapped:
                return edge
        return self.pending_program_edges[0]
If there is an edge with one endpoint mapped, return it.
        Else return in the first edge