public boolean contains(final T value) {
    return values.contains(value);
  }
@Test
  public void shouldReturnCorrectForContainsWithEmptySet() {
    // Given:
    CompatibleSet<CompatibleInteger> compatibleSet = new CompatibleSet<>(
        ImmutableSet.<CompatibleInteger>of());

    // When: Then:
    assertThat(compatibleSet.contains(one), is(false));
    assertThat(compatibleSet.contains(two), is(false));
    assertThat(compatibleSet.contains(three), is(false));
    assertThat(compatibleSet.contains(four), is(false));
  }