test to ensure we pop attr from dict

def test_forward_on_observed_raises_error(observed):

    with pytest.raises(RuntimeError):

        observed()

def test_set_rv_overwrites_attr_in_dict():

    model = module.Module()

    model.test = 1

    assert model.__dict__['test'] ==1

    model.test = dist.Normal(0, 1)

    assert 'test' not in model.__dict__