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
if not dag:
        return {}, ParamsDict()
    dag_args = copy.copy(dag.default_args)
    dag_params = copy.deepcopy(dag.params)
    if task_group:
        if task_group.default_args and not isinstance(task_group.default_args, collections.abc.Mapping):
            raise TypeError("default_args must be a mapping")
        dag_args.update(task_group.default_args)
    return dag_args, dag_params
def get_merged_defaults(
    dag: DAG | None,
    task_group: TaskGroup | None,
    task_params: collections.abc.MutableMapping | None,
    task_default_args: dict | None,
) -> tuple[dict, ParamsDict]:
    args, params = _get_parent_defaults(dag, task_group)
    if task_params:
        if not isinstance(task_params, collections.abc.Mapping):
            raise TypeError("params must be a mapping")
        params.update(task_params)
    if task_default_args:
        if not isinstance(task_default_args, collections.abc.Mapping):
            raise TypeError("default_args must be a mapping")
        args.update(task_default_args)
        with contextlib.suppress(KeyError):
            params.update(task_default_args["params"] or {})
    return args, params
class _PartialDescriptor: