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
serialized = {
            "__version": 1,
            "dag": {
                "_dag_id": "simple_dag",
                "fileloc": "/path/to/file.py",
                "tasks": [],
                "timezone": "UTC",
                "params": {
                    "my_param": {
                        "default": "a string value",
                        "description": "hello",
                        "schema": {"__var": {"type": "string"}, "__type": "dict"},
                        "__class": "airflow.models.param.Param",
                    }
                },
            },
        }
        SerializedDAG.validate_schema(serialized)
        dag = SerializedDAG.from_dict(serialized)
        assert dag.params["my_param"] == "a string value"
        param = dag.params.get_param("my_param")
        assert isinstance(param, Param)
        assert param.description == "hello"
        assert param.schema == {"type": "string"}
    def test_not_templateable_fields_in_serialized_dag(