ImmutableSet<Integer> elements = ImmutableSet.of(1, 2, 3, 4);
    Set<Set<Integer>> forward = powerSet(elements);
    Set<Set<Integer>> reverse = powerSet(ImmutableSet.copyOf(elements.asList().reverse()));
    new EqualsTester().addEqualityGroup(forward, reverse).testEquals();
  }

  /**
   * Test that a hash code miscomputed by "input.hashCode() * tooFarValue / 2" is correct under our

  }

  /**
   * Returns a builder that creates immutable sorted maps whose keys are ordered by the reverse of
   * their natural ordering.
   */
  public static <K extends Comparable<?>, V> Builder<K, V> reverseOrder() {
    return new Builder<>(Ordering.<K>natural().reverse());
  }

  /**
   * A builder for creating immutable sorted map instances, especially {@code public static final}

    @J2ktIncompatible
    private static final long serialVersionUID = 0;
  }

  /**
   * Copies each key-value mapping in {@code source} into {@code dest}, with its key and value
   * reversed.
   *
   * <p>If {@code source} is an {@link ImmutableMultimap}, consider using {@link
   * ImmutableMultimap#inverse} instead.
   *
   * @param source any multimap

    MapDifference<Integer, String> same = Maps.difference(left, right);
    MapDifference<Integer, String> reverse = Maps.difference(right, left);
    MapDifference<Integer, String> diff2 = Maps.difference(left, right2);

    new EqualsTester()
        .addEqualityGroup(original, same)
        .addEqualityGroup(reverse)
        .addEqualityGroup(diff2)
        .testEquals();
  }

    MapDifference<Integer, String> same = Maps.difference(left, right);
    MapDifference<Integer, String> reverse = Maps.difference(right, left);
    MapDifference<Integer, String> diff2 = Maps.difference(left, right2);

    new EqualsTester()
        .addEqualityGroup(original, same)
        .addEqualityGroup(reverse)
        .addEqualityGroup(diff2)
        .testEquals();
  }

  }

  /**
   * Returns a builder that creates immutable sorted maps whose keys are ordered by the reverse of
   * their natural ordering.
   */
  public static <K extends Comparable<?>, V> Builder<K, V> reverseOrder() {
    return new Builder<>(Ordering.<K>natural().reverse());
  }

  /**
   * A builder for creating immutable sorted map instances, especially {@code public static final}

  private Listener clearListeners(@CheckForNull Listener onto) {
    // We need to
    // 1. atomically swap the listeners with TOMBSTONE, this is because addListener uses that
    //    to synchronize with us
    // 2. reverse the linked list, because despite our rather clear contract, people depend on us
    //    executing listeners in the order they were added
    // 3. push all the items onto 'onto' and return the new head of the stack

      if (forwardComparator == null) {
        return (Comparator) Ordering.natural().reverse();
      } else {
        return reverse(forwardComparator);
      }
    }

    // If we inline this, we get a javac error.
    private static <T extends @Nullable Object> Ordering<T> reverse(Comparator<T> forward) {
      return Ordering.from(forward).reverse();
    }

    @Override
    @ParametricNullness

  /**
   * Returns the index of the last matching BMP character in a character sequence, or {@code -1} if
   * no matching character is present.
   *
   * <p>The default implementation iterates over the sequence in reverse order calling {@link
   * #matches} for each character.
   *
   * @param sequence the character sequence to examine from the end
   * @return an index, or {@code -1} if no character matches
   */

   * Returns the set of interfaces and classes that this type is or is a subtype of. The returned
   * types are parameterized with proper type arguments.
   *
   * <p>Subtypes are always listed before supertypes. But the reverse is not true. A type isn't
   * necessarily a subtype of all the types following. Order between types without subtype
   * relationship is arbitrary and not guaranteed.
   *