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
{
            (
                "scheduler",
                "dependency_detector",
            ): "tests.serialization.test_dag_serialization.CustomDependencyDetector"
        }
    )
    def test_custom_dep_detector(self):
        """
        Prior to deprecation of custom dependency detector, the return type was DagDependency | None.
        This class verifies that custom dependency detector classes which assume that return type will still
        work until support for them is removed in 3.0.
        TODO: remove in Airflow 3.0
        """
        from airflow.sensors.external_task import ExternalTaskSensor
        execution_date = datetime(2020, 1, 1)
        with DAG(dag_id="test", start_date=execution_date) as dag:
            ExternalTaskSensor(
                task_id="task1",
                external_dag_id="external_dag_id",
                mode="reschedule",
            )
            CustomDepOperator(task_id="hello", bash_command="hi")
            dag = SerializedDAG.to_dict(dag)
            assert sorted(dag["dag"]["dag_dependencies"], key=lambda x: tuple(x.values())) == sorted(
                [
                    {
                        "source": "external_dag_id",
                        "target": "test",
                        "dependency_type": "sensor",