Ensure that this works:

```python
@setup
def mytask():
    print("I am a setup task")

with dag_maker() as dag:
    mytask.override(task_id='newtask')

assert len(dag.task_group.children) == 1
setup_task = dag.task_group.children["newtask"]
assert setup_task._is_setup
```
and teardown also works
"""Verify serialization fails without timetable registration."""
        dag = get_timetable_based_simple_dag(CustomSerializationTimetable("bar"))
        with pytest.raises(SerializationError) as ctx:
            SerializedDAG.to_dict(dag)
        message = (
            "Failed to serialize DAG 'simple_dag': Timetable class "
            "'tests.test_utils.timetables.CustomSerializationTimetable' "
            "is not registered or "
            "you have a top level database access that disrupted the session. "
            "Please check the airflow best practices documentation."
        )
        assert str(ctx.value) == message
    def validate_serialized_dag(self, json_dag, ground_truth_dag):
        """Verify serialized DAGs match the ground truth."""
        assert json_dag["dag"]["fileloc"].split("/")[-1] == "test_dag_serialization.py"
        json_dag["dag"]["fileloc"] = None
        def sorted_serialized_dag(dag_dict: dict):
            """
            Sorts the "tasks" list and "access_control" permissions in the
            serialised dag python dictionary. This is needed as the order of
            items should not matter but assertEqual would fail if the order of
            items changes in the dag dictionary
            """
            dag_dict["dag"]["tasks"] = sorted(dag_dict["dag"]["tasks"], key=lambda x: sorted(x.keys()))
            dag_dict["dag"]["_access_control"]["__var"]["test_role"]["__var"] = sorted(
                dag_dict["dag"]["_access_control"]["__var"]["test_role"]["__var"]
            )
            return dag_dict
        assert sorted_serialized_dag(ground_truth_dag) == sorted_serialized_dag(json_dag)
    def test_deserialization_across_process(self):