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
TaskGroupContext.push_context_managed_task_group(self)
        return self
    def __exit__(self, _type, _value, _tb):
        TaskGroupContext.pop_context_managed_task_group()
    def has_task(self, task: BaseOperator) -> bool:
        """Returns True if this TaskGroup or its children TaskGroups contains the given task."""
        if task.task_id in self.children:
            return True
        return any(child.has_task(task) for child in self.children.values() if isinstance(child, TaskGroup))
    @property
    def roots(self) -> list[BaseOperator]:
        """Required by TaskMixin"""
        return list(self.get_roots())
    @property
    def leaves(self) -> list[BaseOperator]: