def rz_angles_after(self) -> tuple[cirq.TParamVal, cirq.TParamVal]:
        """Returns 2-tuple of phase angles applied to qubits after FSimGate."""
        a0 = (-self.gamma + self.zeta - self.chi) / 2.0
        a1 = (-self.gamma - self.zeta + self.chi) / 2.0
        return a0, a1
Returns 2-tuple of phase angles applied to qubits after FSimGate.
cirq-core/cirq/ops/fsim_gate.py