'Check that we can use Quantity if we have subok=True'

def test_using_quantity_class(self):

    lu = u.dex(u.AA)
    with pytest.raises(u.UnitTypeError):
        u.Quantity(1.0, lu)
    q = u.Quantity(1.0, lu, subok=True)
    assert (type(q) is lu._quantity_class)
