def on(self, q0: ops.Qid, q1: ops.Qid) -> ops.Operation:
        """Returns the operation that replaces the two qubit gate."""
        if self.swap_qubits:
            return self.two_qubit_gate(q1, q0)
        return self.two_qubit_gate(q0, q1)
Returns the operation that replaces the two qubit gate.
cirq-core/cirq/transformers/gauge_compiling/gauge_compiling.py