Returns the multiplication of two matrices.

def mult_matrix(m1, m0):
    (a1, b1, c1, d1, e1, f1) = m1
    (a0, b0, c0, d0, e0, f0) = m0
    """Returns the multiplication of two matrices."""
    return (a0*a1+c0*b1,    b0*a1+d0*b1,
            a0*c1+c0*d1,    b0*c1+d0*d1,
            a0*e1+c0*f1+e0, b0*e1+d0*f1+f0)