/**
   * Returns the next element in the iteration, without advancing the iteration.
   *
   * <p>Calls to {@code peek()} should not change the state of the iteration, except that it
   * <i>may</i> prevent removal of the most recent element via {@link #remove()}.
   *
   * @throws NoSuchElementException if the iteration has no more elements according to {@link
   *     #hasNext()}
   */
  @ParametricNullness

     * If {@code element} is not {@code null}, child configuration element with the specified name will
     * be unmarshalled.
     *
     * @param configuration The configuration to unmarshal, may be {@code null}.
     * @param element Configuration element name to unmarshal or {@code null} to unmarshal entire configuration.

    }

    @Override
    public @Nullable E peek() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.peek();
    }

    @Override
    public E element() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.element();
    }

    @Override
    public Iterator<E> iterator() {
      // We explicitly don't lock for iterator()
      assertFalse(Thread.holdsLock(mutex));

  /** Constructor for use by subclasses. */
  protected ForwardingListIterator() {}

  @Override
  protected abstract ListIterator<E> delegate();

  @Override
  public void add(@ParametricNullness E element) {
    delegate().add(element);
  }

  @Override
  public boolean hasPrevious() {
    return delegate().hasPrevious();
  }

  @Override
  public int nextIndex() {
    return delegate().nextIndex();
  }

   * nulls as long as the *last* element is *not* null.
   *
   * (To "go out of its way," the method tracks a `set` bit so that it can distinguish "the final
   * split has a last element of null, so throw NPE" from "the final split was empty, so look for an
   * element in the prior one.")
   */
  public static <T> java.util.Optional<T> findLast(Stream<T> stream) {
    final class OptionalState {
      boolean set = false;

        Element rootElement = parentPom.root();
        if (rootElement == null) {
            return;
        }

        // Find modules element
        Element modulesElement = rootElement.child(MODULES).orElse(null);
        if (modulesElement == null) {
            return;
        }

        // Process each module

                  public Set<Cell<String, Integer, Character>> create(Object... elements) {
                    List<Integer> columnKeys = new ArrayList<>();
                    for (Object element : elements) {
                      @SuppressWarnings("unchecked")
                      Cell<String, Integer, Character> cell =
                          (Cell<String, Integer, Character>) element;
                      columnKeys.add(cell.getColumnKey());

                  public Set<Cell<String, Integer, Character>> create(Object... elements) {
                    List<Integer> columnKeys = new ArrayList<>();
                    for (Object element : elements) {
                      @SuppressWarnings("unchecked")
                      Cell<String, Integer, Character> cell =
                          (Cell<String, Integer, Character>) element;
                      columnKeys.add(cell.getColumnKey());

   * IllegalArgumentException}.
   */
  @Override
  boolean allowsSelfLoops();

  /** Returns the order of iteration for the elements of {@link #nodes()}. */
  @Override
  ElementOrder<N> nodeOrder();

  /**
   * Returns an {@link ElementOrder} that specifies the order of iteration for the elements of
   * {@link #edges()}, {@link #adjacentNodes(Object)}, {@link #predecessors(Object)}, {@link

  private static final @Nullable String NE = null;

  private static <E extends @Nullable Object> Entry<E> entry(E element, int count) {
    return Multisets.immutableEntry(element, count);
  }

  private static <E extends @Nullable Object> Entry<E> control(E element, int count) {
    return HashMultiset.create(nCopies(count, element)).entrySet().iterator().next();
  }

  public void testToString() {