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 this TaskGroup has immediate upstream TaskGroups or tasks, a proxy node called
        upstream_join_id will be created in Graph view to join the outgoing edges from this
        TaskGroup to reduce the total number of edges needed to be displayed.
        """
        return f"{self.group_id}.upstream_join_id"
    @property
    def downstream_join_id(self) -> str:
        """
        If this TaskGroup has immediate downstream TaskGroups or tasks, a proxy node called
        downstream_join_id will be created in Graph view to join the outgoing edges from this
        TaskGroup to reduce the total number of edges needed to be displayed.
        """
        return f"{self.group_id}.downstream_join_id"
    def get_task_group_dict(self) -> dict[str, TaskGroup]:
        """Returns a flat dictionary of group_id: TaskGroup"""
        task_group_map = {}
        def build_map(task_group):
            if not isinstance(task_group, TaskGroup):
                return
            task_group_map[task_group.group_id] = task_group
            for child in task_group.children.values():
                build_map(child)
        build_map(self)
        return task_group_map
    def get_child_by_label(self, label: str) -> DAGNode: