@Override
    public Entry<K, Collection<V>>[] createArray(int length) {
      return (Entry<K, Collection<V>>[]) new Entry<?, ?>[length];
    }

    @Override
    public Iterable<Entry<K, Collection<V>>> order(List<Entry<K, Collection<V>>> insertionOrder) {
      Map<K, Collection<V>> map = new HashMap<>();
      List<Entry<K, V>> builder = new ArrayList<>();
      for (Entry<K, Collection<V>> entry : insertionOrder) {

   */
  public static boolean elementsEqual(Iterable<?> iterable1, Iterable<?> iterable2) {
    if (iterable1 instanceof Collection && iterable2 instanceof Collection) {
      Collection<?> collection1 = (Collection<?>) iterable1;
      Collection<?> collection2 = (Collection<?>) iterable2;
      if (collection1.size() != collection2.size()) {
        return false;
      }
    }

   * words, for the default {@code expectContents()} implementation, the number of occurrences of
   * each given element has increased by one since the test collection was created, and the number
   * of occurrences of all other elements has not changed.
   *
   * <p>Note: This means that a test like the following will fail if {@code collection} is a {@code
   * Set}:
   *
   * <pre>

  }

  @Override
  public boolean containsAll(Collection<?> collection) {
    if (!allowNulls) {
      for (Object object : collection) {
        // behave badly
        if (object == null) {
          throw new NullPointerException();
        }
      }
    }
    return super.containsAll(collection);
  }

  @Override
  public Iterator<E> iterator() {

  @GwtIncompatible
  @J2ktIncompatible
  private static final class SerializedForm implements Serializable {
    final ImmutableCollection<?> collection;

    SerializedForm(ImmutableCollection<?> collection) {
      this.collection = collection;
    }

    Object readResolve() {
      return collection.asList();
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  @GwtIncompatible

     */
    @Nonnull
    ChecksumAlgorithm select(@Nonnull String algorithmName);

    /**
     * Returns a collection of {@link ChecksumAlgorithm} in same order as algorithm names are ordered, or throws if
     * any of the algorithm name is not supported. The returned collection has equal count of elements as passed in
     * collection of names, and if names contains duplicated elements, the returned list of algorithms will have
     * duplicates as well.

  }

  @Override
  public boolean add(E element) {
    return delegate.add(checkValid(element));
  }

  @Override
  public boolean addAll(Collection<? extends E> collection) {
    for (E e : collection) {
      checkValid(e);
    }
    return delegate.addAll(collection);
  }

  @Override
  public @Nullable E ceiling(E e) {
    return delegate.ceiling(checkValid(e));
  }

  @Override
  public void clear() {

  @Override
  Collection<V> wrapCollection(@ParametricNullness K key, Collection<V> collection) {
    return new WrappedSet(key, (Set<V>) collection);
  }

  // Following Javadoc copied from SetMultimap.

  /**
   * {@inheritDoc}
   *
   * <p>Because a {@code SetMultimap} has unique values for a given key, this method returns a
   * {@link Set}, instead of the {@link Collection} specified in the {@link Multimap} interface.
   */
  @Override

  @Override
  Collection<V> wrapCollection(@ParametricNullness K key, Collection<V> collection) {
    return new WrappedSet(key, (Set<V>) collection);
  }

  // Following Javadoc copied from SetMultimap.

  /**
   * {@inheritDoc}
   *
   * <p>Because a {@code SetMultimap} has unique values for a given key, this method returns a
   * {@link Set}, instead of the {@link Collection} specified in the {@link Multimap} interface.
   */
  @Override

   * elements than the collection), the element in the array immediately following the end of the
   * collection is set to {@code null}. This is useful in determining the length of the collection
   * <i>only</i> if the caller knows that the collection does not contain any null elements.
   *
   * <p>This method returns the elements in the order they are returned by the collection's
   * iterator.
   *