private @Nullable A unsafeDoBackward(@Nullable B b) {
    return doBackward(uncheckedCastNullableTToT(b));
  }

  /**
   * Returns an iterable that applies {@code convert} to each element of {@code fromIterable}. The
   * conversion is done lazily.
   *
   * <p>The returned iterable's iterator supports {@code remove()} if the input iterator does. After

      Iterable<? extends Comparator<? super T>> comparators) {
    return new CompoundOrdering<>(comparators);
  }

  /**
   * Returns a new ordering which sorts iterables by comparing corresponding elements pairwise until
   * a nonzero result is found; imposes "dictionary order". If the end of one iterable is reached,
   * but not the other, the shorter iterable is considered to be less than the longer one. For

      Iterable<? extends Comparator<? super T>> comparators) {
    return new CompoundOrdering<>(comparators);
  }

  /**
   * Returns a new ordering which sorts iterables by comparing corresponding elements pairwise until
   * a nonzero result is found; imposes "dictionary order". If the end of one iterable is reached,
   * but not the other, the shorter iterable is considered to be less than the longer one. For

   *
   * <p><b>Warning:</b> {@code File} provides no support for symbolic links, and as such there is no
   * way to ensure that a symbolic link to a directory is not followed when traversing the tree. In
   * this case, iterables created by this traverser could contain files that are outside of the
   * given directory or even be infinite if there is a symbolic link loop.
   *

    assertEqualCharNodes(result, "bfaecd");
  }

  @Test
  public void forGraph_breadthFirst_infinite() {
    Iterable<Integer> result =
        Traverser.forGraph(fixedSuccessors(Iterables.cycle(1, 2, 3))).breadthFirst(0);
    assertThat(Iterables.limit(result, 4)).containsExactly(0, 1, 2, 3).inOrder();
  }

  @Test
  public void forGraph_breadthFirst_diamond() {

  static final Iterable<Double> INFINITIES =
      Doubles.asList(Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY);
  static final Iterable<Double> FINITE_DOUBLE_CANDIDATES;
  static final Iterable<Double> POSITIVE_FINITE_DOUBLE_CANDIDATES;
  static final Iterable<Double> ALL_DOUBLE_CANDIDATES;
  static final Iterable<Double> DOUBLE_CANDIDATES_EXCEPT_NAN;

  static {

  private @Nullable A unsafeDoBackward(@Nullable B b) {
    return doBackward(uncheckedCastNullableTToT(b));
  }

  /**
   * Returns an iterable that applies {@code convert} to each element of {@code fromIterable}. The
   * conversion is done lazily.
   *
   * <p>The returned iterable's iterator supports {@code remove()} if the input iterator does. After

   */
  private Iterable<List<Object>> buildCartesianProduct(Set<?>... sets) {
    List<Set<Optional<?>>> optionalSets = Lists.newArrayListWithExpectedSize(sets.length);
    for (Set<?> set : sets) {
      Set<Optional<?>> optionalSet =
          Sets.newLinkedHashSet(Iterables.transform(set, Optional::fromNullable));
      optionalSets.add(optionalSet);
    }

   * they are returned by the iterable's iterator.
   *
   * @since 12.0
   */
  public static <E> ArrayDeque<E> newArrayDeque(Iterable<? extends E> elements) {
    if (elements instanceof Collection) {
      return new ArrayDeque<>((Collection<? extends E>) elements);
    }
    ArrayDeque<E> deque = new ArrayDeque<>();
    Iterables.addAll(deque, elements);
    return deque;

 * <p>There are two ways to obtain a {@code Stats} instance:
 *
 * <ul>
 *   <li>If all the values you want to summarize are already known, use the appropriate {@code
 *       Stats.of} factory method below. Primitive arrays, iterables and iterators of any kind of
 *       {@code Number}, and primitive varargs are supported.
 *   <li>Or, to avoid storing up all the data first, create a {@link StatsAccumulator} instance,