def METHOD_NAME(self, ethane):
    for part in ethane:
        part.element = part.name
    compound_to_json(ethane, "ethane.json")
    ethane_copy = compound_from_json("ethane.json")
    for part_orig, part_copy in zip(ethane, ethane_copy):
        assert part_orig.element.symbol == part_copy.element.symbol
    assert ethane.n_particles == ethane_copy.n_particles
    assert ethane.n_bonds == ethane_copy.n_bonds
    assert len(ethane.children) == len(ethane_copy.children)