def global_phase_operation(
    coefficient: cirq.TParamValComplex, atol: float = 1e-8
) -> cirq.GateOperation:
    """Creates an operation that represents a global phase on the state."""
    return GlobalPhaseGate(coefficient, atol)()
Creates an operation that represents a global phase on the state.
cirq-core/cirq/ops/global_phase_op.py