def full_invert_mask(self) -> tuple[bool, ...]:
        """Returns the invert mask for all qubits.

        If the user supplies a partial invert_mask, this returns that mask
        padded by False.

        Similarly if no invert_mask is supplies this returns a tuple
        of size equal to the number of qubits with all entries False.
        """
        mask = self.invert_mask or self.num_qubits() * (False,)
        deficit = self.num_qubits() - len(mask)
        mask += (False,) * deficit
        return mask
Returns the invert mask for all qubits.

        If the user supplies a partial invert_mask, this returns that mask
        padded by False.

        Similarly if no invert_mask is supplies this returns a tuple
        of size equal to the number of qubits with all entries False.
        
cirq-core/cirq/ops/measurement_gate.py