'for fun, a more complicated example of addition and subtraction'

def test_complicated_addition_subtraction(self):

    dm0 = u.Unit(u'DM', (1.0 / ((4.0 * np.pi) * ((10.0 * u.pc) ** 2))))
    lu_dm = u.mag(dm0)
    lu_absST = (u.STmag - lu_dm)
    assert lu_absST.is_equivalent(((u.erg / u.s) / u.AA))
