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
deps = frozenset(list(BaseOperator.deps) + [CustomTestTriggerRule()])
        execution_date = datetime(2020, 1, 1)
        with DAG(dag_id="test_serialize_custom_ti_deps", start_date=execution_date) as dag:
            DummyTask(task_id="task1")
        serialize_op = SerializedBaseOperator.serialize_operator(dag.task_dict["task1"])
        assert serialize_op["deps"] == [
            "airflow.ti_deps.deps.not_in_retry_period_dep.NotInRetryPeriodDep",
            "airflow.ti_deps.deps.not_previously_skipped_dep.NotPreviouslySkippedDep",
            "airflow.ti_deps.deps.prev_dagrun_dep.PrevDagrunDep",
            "airflow.ti_deps.deps.trigger_rule_dep.TriggerRuleDep",
            "test_plugin.CustomTestTriggerRule",
        ]
        op = SerializedBaseOperator.deserialize_operator(serialize_op)
        assert sorted(str(dep) for dep in op.deps) == [
            "<TIDep(CustomTestTriggerRule)>",
            "<TIDep(Not In Retry Period)>",
            "<TIDep(Not Previously Skipped)>",
            "<TIDep(Previous Dagrun State)>",
            "<TIDep(Trigger Rule)>",
        ]
    def test_serialize_mapped_outlets(self):