def to_exponent(angle_rads: cirq.TParamVal) -> cirq.TParamVal:
            """Divides angle_rads by symbolic or numerical pi."""
            pi = sympy.pi if protocols.is_parameterized(angle_rads) else np.pi
            return angle_rads / pi
Divides angle_rads by symbolic or numerical pi.
cirq-core/cirq/ops/fsim_gate.py