def test_arbit_class():

    class Foo(object):
        pass
    with pytest.raises(ValueError):

        @task
        def t1(a: int) -> Foo:
            return Foo()
def test_arbit_class():

    class Foo(object):
        pass
    with pytest.raises(ValueError):

        @task
        def t1(a: int) -> Foo:
            return Foo()