raise Exception
        with dag_maker():
            ret = f()
        with pytest.raises(CalledProcessError):
            ret.operator.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE)
    def test_with_args(self, dag_maker, venv_python):
        @task.external_python(python=venv_python)
        def f(a, b, c=False, d=False):
            if a == 0 and b == 1 and c and not d:
                return True
            else:
                raise Exception
        with dag_maker():
            ret = f(0, 1, c=True)
        ret.operator.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE)
    def test_return_none(self, dag_maker, venv_python):
        @task.external_python(python=venv_python)
        def f():
            return None
        with dag_maker():
            ret = f()
        ret.operator.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE)
    def test_nonimported_as_arg(self, dag_maker, venv_python):
        @task.external_python(python=venv_python)
        def f(_):
            return None
        with dag_maker():
            ret = f(datetime.datetime.utcnow())
        ret.operator.run(start_date=DEFAULT_DATE, end_date=DEFAULT_DATE)