@Override
    public Optional<DiscreteResource> parent() {
        return id.parent().map(x -> Resources.discrete(x).resource());
    }
@Test
    public void testThereIsParent() {
        DiscreteResource resource = Resources.discrete(D1, P1, VLAN1).resource();
        DiscreteResource parent = Resources.discrete(D1, P1).resource();

        assertThat(resource.parent(), is(Optional.of(parent)));
    }