def METHOD_NAME(G: Graph) -> None:
    assert set(G.relationship_properties("REL")) == {"y", "z"}
    assert G.relationship_properties("REL2") == ["q"]
    rel_properties = G.relationship_properties()
    assert isinstance(rel_properties, Series)
    assert rel_properties.size == 2
    assert set(rel_properties["REL"]) == {"y", "z"}
    assert rel_properties["REL2"] == ["q"]