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
t2.set_downstream(t5)
        t2.set_downstream(t6)
        t3.set_downstream(t4)
        t3.set_downstream(t5)
        t3.set_downstream(t6)
    Using task-decorated functions aka XComArgs:
    .. code-block:: python
        cross_downstream(from_tasks=[x1(), x2(), x3()], to_tasks=[x4(), x5(), x6()])
    is equivalent to::
        x1 ---> x4
           \ /
        x2 -X -> x5
           / \
        x3 ---> x6
    .. code-block:: python
        x1 = x1()
        x2 = x2()
        x3 = x3()
        x4 = x4()
        x5 = x5()
        x6 = x6()
        x1.set_downstream(x4)
        x1.set_downstream(x5)
        x1.set_downstream(x6)
        x2.set_downstream(x4)
        x2.set_downstream(x5)
        x2.set_downstream(x6)
        x3.set_downstream(x4)
        x3.set_downstream(x5)
        x3.set_downstream(x6)