* over keys in the order they were first encountered in the input, and the values for each key
   * are iterated in the order they were encountered.
   *
   * @throws NullPointerException if any key, value, or entry is null
   * @since 19.0
   */
  public static <K, V> ImmutableListMultimap<K, V> copyOf(
      Iterable<? extends Entry<? extends K, ? extends V>> entries) {

   * @since 24.1
   */
  public final Iterable<N> breadthFirst(Iterable<? extends N> startNodes) {
    ImmutableSet<N> validated = validate(startNodes);
    return new Iterable<N>() {
      @Override
      public Iterator<N> iterator() {
        return newTraversal().breadthFirst(validated.iterator());
      }
    };
  }

  /**
   * Returns an unmodifiable {@code Iterable} over the nodes reachable from {@code startNode}, in

   *     original iterable.
   * @throws NullPointerException if the specified iterable is null or has any null elements.
   * @since 12.0
   */
  public static <E extends Comparable<? super E>> Collection<List<E>> orderedPermutations(
      Iterable<E> elements) {
    return orderedPermutations(elements, Ordering.natural());
  }

  /**
   * Returns a {@link Collection} of all the permutations of the specified {@link Iterable} using

       * documented in the Javadoc. If a row Comparator is provided, cellSet() iterates across the
       * columns in the first row, the columns in the second row, etc. If a column Comparator is
       * provided but a row Comparator isn't, cellSet() iterates across the rows in the first
       * column, the rows in the second column, etc.
       */
      Comparator<Cell<R, C, V>> comparator =

   */
  static DoubleStream megaPrimitiveDoubleStream() {
    return DoubleStream.iterate(0.0, x -> x + 1.0).limit(MEGA_STREAM_COUNT).parallel();
  }

  /** Returns a stream containing half the values from {@link #megaPrimitiveDoubleStream}. */
  static DoubleStream megaPrimitiveDoubleStreamPart1() {
    return DoubleStream.iterate(0.0, x -> x + 2.0).limit(MEGA_STREAM_COUNT / 2).parallel();
  }

  /**

   * over keys in the order they were first encountered in the input, and the values for each key
   * are iterated in the order they were encountered.
   *
   * @throws NullPointerException if any key, value, or entry is null
   * @since 19.0
   */
  public static <K, V> ImmutableMultimap<K, V> copyOf(
      Iterable<? extends Entry<? extends K, ? extends V>> entries) {

   * over keys in the order they were first encountered in the input, and the values for each key
   * are iterated in the order they were encountered.
   *
   * @throws NullPointerException if any key, value, or entry is null
   * @since 19.0
   */
  public static <K, V> ImmutableListMultimap<K, V> copyOf(
      Iterable<? extends Entry<? extends K, ? extends V>> entries) {

    Iterable<String> iterable = iterable("a", null, "b");
    assertTrue(FluentIterable.from(iterable).contains(null));
  }

  public void testContains_nullIterableNo() {
    Iterable<String> iterable = iterable("a", "b");
    assertFalse(FluentIterable.from(iterable).contains(null));
  }

  public void testContains_nonNullSetYes() {
    Iterable<String> set = Sets.newHashSet("a", null, "b");

      final Function<T, ? extends Iterable<T>> nodeToChildrenFunction) {
    checkNotNull(nodeToChildrenFunction);
    return new TreeTraverser<T>() {
      @Override
      public Iterable<T> children(T root) {
        return nodeToChildrenFunction.apply(root);
      }
    };
  }

  /** Returns the children of the specified node. Must not contain null. */
  public abstract Iterable<T> children(T root);

  /**

   * over keys in the order they were first encountered in the input, and the values for each key
   * are iterated in the order they were encountered.
   *
   * @throws NullPointerException if any key, value, or entry is null
   * @since 19.0
   */
  public static <K, V> ImmutableMultimap<K, V> copyOf(
      Iterable<? extends Entry<? extends K, ? extends V>> entries) {