protected final K k3() {
    return e3().getKey();
  }

  protected final V v3() {
    return e3().getValue();
  }

  protected final K k4() {
    return e4().getKey();
  }

  protected final V v4() {
    return e4().getValue();
  }

    putAll(createDisjointCollection());
    expectAdded(e3(), e4());
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)
  public void testPutAll_unsupportedNonePresent() {
    assertThrows(UnsupportedOperationException.class, () -> putAll(createDisjointCollection()));
    expectUnchanged();
    expectMissing(e3(), e4());
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)

        colliders.e0(), 0,
        colliders.e1(), 1,
        colliders.e2(), 2,
        colliders.e3(), 3);
  }

  @Override
  protected Object getKeyNotInPopulatedMap() {
    return new Colliders().e4();
  }

  @Override
  protected Integer getValueNotInPopulatedMap() {
    return 4;
  }

    expectAdded(e3(), e4());
  }

  @CollectionFeature.Require(absent = SUPPORTS_ADD)
  public void testAddAll_unsupportedNonePresent() {
    assertThrows(
        UnsupportedOperationException.class, () -> collection.addAll(createDisjointCollection()));
    expectUnchanged();
    expectMissing(e3(), e4());
  }

  @CollectionFeature.Require(SUPPORTS_ADD)

  }

  protected final E e2() {
    return samples.e2();
  }

  protected final E e3() {
    return samples.e3();
  }

  protected final E e4() {
    return samples.e4();
  }

    putAll(createDisjointCollection());
    expectAdded(e3(), e4());
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)
  public void testPutAll_unsupportedNonePresent() {
    assertThrows(UnsupportedOperationException.class, () -> putAll(createDisjointCollection()));
    expectUnchanged();
    expectMissing(e3(), e4());
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)

   * the first are ignored.
   */
  public static <E> ImmutableSet<E> of(E e1, E e2, E e3, E e4) {
    return new RegularSetBuilderImpl<E>(4).add(e1).add(e2).add(e3).add(e4).review().build();
  }

  /**
   * Returns an immutable set containing the given elements, minus duplicates, in the order each was

      return new SampleElements<>(
          reverse(samples.e0()),
          reverse(samples.e1()),
          reverse(samples.e2()),
          reverse(samples.e3()),
          reverse(samples.e4()));
    }

    private Entry<V, K> reverse(Entry<K, V> entry) {
      checkNotNull(entry);
      return mapEntry(entry.getValue(), entry.getKey());
    }

    @SuppressWarnings("unchecked")

          new SampleElements<>(
              mapSamples.e0().getKey(),
              mapSamples.e1().getKey(),
              mapSamples.e2().getKey(),
              mapSamples.e3().getKey(),
              mapSamples.e4().getKey());
    }

    @Override
    public SampleElements<K> samples() {
      return samples;
    }

    @Override
    public Set<K> create(Object... elements) {

    runListIteratorTest(MODIFIABLE);
  }

  private void runListIteratorTest(Set<IteratorFeature> features) {
    new ListIteratorTester<E>(
        listListIteratorTesterNumIterations(),
        singleton(e4()),
        features,
        copyToList(getOrderedElements()),
        0) {
      @Override
      protected ListIterator<E> newTargetIterator() {
        resetCollection();
        return getList().listIterator();