### Question:
NullIndividualHelper implements IndividualHelper { @Override public Set<URI> types() { return Collections.emptySet(); }  @Override Set<URI> types(); @Override PropertyHelper property(URI propertyId); @Override PropertyHelper property(String propertyId); @Override PropertyHelper property(Term property);  }### Answer:
@Test public void testTypes() throws Exception { assertThat(sut.types(),hasSize(0)); }