'qubits: a set of qubits (Qubit)
Returns: quantum object (quantum expression - QExpr)'

def _apply_operator_Qubit(self, qubits, **options):

    if (qubits.nqubits != self.nqubits):
        raise QuantumError(('WGate    operates    on    %r    qubits,    got:    %r' % (self.nqubits, qubits.nqubits)))
    basis_states = superposition_basis(self.nqubits)
    change_to_basis = ((2 / sqrt((2 ** self.nqubits))) * basis_states)
    return (change_to_basis - qubits)
