* }
   * }</pre>
   *
   * <p>Note that if any input set is empty, the Cartesian product will also be empty. If no sets at
   * all are provided (an empty list), the resulting Cartesian product has one element, an empty
   * list (counter-intuitive, but mathematically consistent).
   *
   * <p><i>Performance notes:</i> while the cartesian product of sets of size {@code m, n, p} is a

      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  /** The 0-ary cartesian product is a single empty list. */
  public void testCartesianProduct_zeroary() {
    assertThat(Sets.cartesianProduct()).containsExactly(list());
  }

  /** A unary cartesian product is one list of size 1 for each element in the input set. */
  public void testCartesianProduct_unary() {

   * for matchers that only match a few characters, and so on. In the worst-case scenario, it
   * constructs an eight-kilobyte bit array and queries that. In many situations this produces a
   * matcher which is faster to query than the original.
   */
  @GwtIncompatible // SmallCharMatcher
  CharMatcher precomputedInternal() {
    final BitSet table = new BitSet();
    setBits(table);

   *     is greater than the number of elements remaining in {@code iterator}
   * @return the element at the specified position in {@code iterator} or {@code defaultValue} if
   *     {@code iterator} produces fewer than {@code position + 1} elements.
   * @throws IndexOutOfBoundsException if {@code position} is negative
   * @since 4.0
   */
  @ParametricNullness
  public static <T extends @Nullable Object> T get(

   *     is greater than the number of elements remaining in {@code iterator}
   * @return the element at the specified position in {@code iterator} or {@code defaultValue} if
   *     {@code iterator} produces fewer than {@code position + 1} elements.
   * @throws IndexOutOfBoundsException if {@code position} is negative
   * @since 4.0
   */
  @ParametricNullness
  public static <T extends @Nullable Object> T get(

   * invariants:
   *
   * <ol>
   *   <li>{@code canonicalize(t)} always produces the equal result for equivalent types. For
   *       example both {@code Enum<?>} and {@code Enum<? extends Enum<?>>} canonicalize to {@code
   *       Enum<? extends Enum<E>}.
   *   <li>{@code canonicalize(t)} produces a "literal" supertype of t. For example: {@code Enum<?

   *     keyFunction} on each value in the input collection to that value
   * @throws NullPointerException if any element of {@code values} is {@code null}, or if {@code
   *     keyFunction} produces {@code null} for any key
   */
  public static <K, V> ImmutableListMultimap<K, V> index(
      Iterable<V> values, Function<? super V, K> keyFunction) {
    return index(values.iterator(), keyFunction);
  }

   * for matchers that only match a few characters, and so on. In the worst-case scenario, it
   * constructs an eight-kilobyte bit array and queries that. In many situations this produces a
   * matcher which is faster to query than the original.
   */
  @GwtIncompatible // SmallCharMatcher
  CharMatcher precomputedInternal() {
    final BitSet table = new BitSet();
    setBits(table);

     *     passed to {@code whenAllSucceed}, if that is the method you used to create this {@code
     *     FutureCombiner}). Even though the future never produces a value other than {@code null},
     *     you should typically check whether it failed: See <a