def METHOD_NAME() -> None:
    cfg = OmegaConf.create({"foo": UnionNode(10, Union[int, str])})
    assert cfg._get_node("foo")._get_full_key(None) == "foo"  # type: ignore
    node = UnionNode(10, Union[int, str])
    assert node._get_full_key(None) == ""
    node = UnionNode(10, Union[int, str], key="foo")
    assert node._get_full_key(None) == "foo"