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
Create a nested dict representation of this TaskGroup and its children used to construct
    the Graph.
    """
    from airflow.models.abstractoperator import AbstractOperator
    if isinstance(task_item_or_group, AbstractOperator):
        return {
            "id": task_item_or_group.task_id,
            "value": {
                "label": task_item_or_group.label,
                "labelStyle": f"fill:{task_item_or_group.ui_fgcolor};",
                "style": f"fill:{task_item_or_group.ui_color};",
                "rx": 5,
                "ry": 5,
            },
        }
    task_group = task_item_or_group
    is_mapped = isinstance(task_group, MappedTaskGroup)
    children = [
        task_group_to_dict(child) for child in sorted(task_group.children.values(), key=lambda t: t.label)
    ]
    if task_group.upstream_group_ids or task_group.upstream_task_ids:
        children.append(
            {
                "id": task_group.upstream_join_id,
                "value": {
                    "label": "",
                    "labelStyle": f"fill:{task_group.ui_fgcolor};",
                    "style": f"fill:{task_group.ui_color};",
                    "shape": "circle",
                },