def __pow__(self, exponent: int) -> cirq.Circuit:
        """A circuit raised to a power, only valid for exponent -1, the inverse.

        This will fail if anything other than -1 is passed to the Circuit by
        returning NotImplemented.  Otherwise this will return the inverse
        circuit, which is the circuit with its moment order reversed and for
        every moment all the moment's operations are replaced by its inverse.
        If any of the operations do not support inverse, NotImplemented will be
        returned.
        """
        if exponent != -1:
            return NotImplemented
        inv_moments = []
        for moment in self[::-1]:
            inv_moment = cirq.inverse(moment, default=NotImplemented)
            if inv_moment is NotImplemented:
                return NotImplemented
            inv_moments.append(inv_moment)

        return cirq.Circuit(inv_moments)
A circuit raised to a power, only valid for exponent -1, the inverse.

        This will fail if anything other than -1 is passed to the Circuit by
        returning NotImplemented.  Otherwise this will return the inverse
        circuit, which is the circuit with its moment order reversed and for
        every moment all the moment's operations are replaced by its inverse.
        If any of the operations do not support inverse, NotImplemented will be
        returned.
        
cirq-core/cirq/circuits/circuit.py