qiskit/quantum_info/operators/pauli.py
def sgn_prod(p1, p2):
        r"""
        Multiply two Paulis and track the phase.

        $P_3 = P_1 \otimes P_2$: X*Y

        Args:
            p1 (Pauli): pauli 1
            p2 (Pauli): pauli 2

        Returns:
            Pauli: the multiplied pauli
            complex: the sign of the multiplication, 1, -1, 1j or -1j
        """
        phase = Pauli._prod_phase(p1, p2)
        new_pauli = p1 * p2
        return new_pauli, phase
def sgn_prod(p1, p2):
        r"""
        Multiply two Paulis and track the phase.

        $P_3 = P_1 \otimes P_2$: X*Y

        Args:
            p1 (Pauli): pauli 1
            p2 (Pauli): pauli 2

        Returns:
            Pauli: the multiplied pauli
            complex: the sign of the multiplication, 1, -1, 1j or -1j
        """
        phase = Pauli._prod_phase(p1, p2)
        new_pauli = p1 * p2
        return new_pauli, phase
r"""
        Multiply two Paulis and track the phase.

        $P_3 = P_1 \otimes P_2$: X*Y

        Args:
            p1 (Pauli): pauli 1
            p2 (Pauli): pauli 2

        Returns:
            Pauli: the multiplied pauli
            complex: the sign of the multiplication, 1, -1, 1j or -1j