}

  private static final ImmutableMap<Class<?>, Method> EMPTY_GENERATORS;

  static {
    ImmutableMap.Builder<Class<?>, Method> builder = ImmutableMap.builder();
    for (Method method : FreshValueGenerator.class.getDeclaredMethods()) {
      if (method.isAnnotationPresent(Empty.class)) {
        builder.put(method.getReturnType(), method);
      }
    }
    EMPTY_GENERATORS = builder.buildOrThrow();
  }

   * If {@code iterable} is a {@link List} with {@link RandomAccess} support, then this operation is
   * guaranteed to be {@code O(1)}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@code Streams.findLast(stream).orElse(defaultValue)}
   *
   * @param defaultValue the value to return if {@code iterable} is empty

    return CollectCollectors.toImmutableRangeSet();
  }

  /**
   * Returns an empty immutable range set.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings("unchecked")
  public static <C extends Comparable> ImmutableRangeSet<C> of() {
    return (ImmutableRangeSet<C>) EMPTY;
  }

  /**

          Function<? super T, ? extends Stream<? extends V>> valuesFunction) {
    return CollectCollectors.flatteningToImmutableSetMultimap(keyFunction, valuesFunction);
  }

  /**
   * Returns the empty multimap.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  // Casting is safe because the multimap will never hold any elements.
  @SuppressWarnings("unchecked")

  }

  /**
   * Returns an empty immutable range map.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings("unchecked")
  public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> of() {
    return (ImmutableRangeMap<K, V>) EMPTY;
  }

  /** Returns an immutable range map mapping a single range to a single value. */

      @SuppressWarnings("unchecked") // The natural-ordered empty set supports all types.
      RegularImmutableSortedSet<E> result =
          (RegularImmutableSortedSet<E>) RegularImmutableSortedSet.NATURAL_EMPTY_SET;
      return result;
    } else {
      return new RegularImmutableSortedSet<>(ImmutableList.of(), comparator);
    }
  }

  /**
   * Returns the empty immutable sorted set.
   *

  }

  private static final ImmutableMap<Class<?>, Method> EMPTY_GENERATORS;

  static {
    ImmutableMap.Builder<Class<?>, Method> builder = ImmutableMap.builder();
    for (Method method : FreshValueGenerator.class.getDeclaredMethods()) {
      if (method.isAnnotationPresent(Empty.class)) {
        builder.put(method.getReturnType(), method);
      }
    }
    EMPTY_GENERATORS = builder.buildOrThrow();
  }

   *     // operate on tuple
   *   }
   * }
   * }</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).
   *

   * @throws NullPointerException if any element in the stream is {@code null}.
   * @return {@code Optional.of(onlyElement)} if the stream has exactly one element (must not be
   *     {@code null}) and returns {@code Optional.empty()} if it has none.
   */
  @SuppressWarnings("unchecked")
  public static <T> Collector<T, ?, Optional<T>> toOptional() {
    return (Collector) TO_OPTIONAL;
  }

   * uses less memory than TreeMap; then say so in the class Javadoc.
   */
  private static final Comparator<?> NATURAL_ORDER = Ordering.natural();

  private static final ImmutableSortedMap<Comparable<?>, Object> NATURAL_EMPTY_MAP =
      new ImmutableSortedMap<>(
          ImmutableSortedSet.emptySet(Ordering.natural()), ImmutableList.<Object>of());

  static <K, V> ImmutableSortedMap<K, V> emptyMap(Comparator<? super K> comparator) {