* corresponding keys.
   */
  @Override
  public ImmutableCollection<V> values() {
    return valueList;
  }

  @Override
  ImmutableCollection<V> createValues() {
    throw new AssertionError("should never be called");
  }

  /**
   * Returns the comparator that orders the keys, which is {@link Ordering#natural()} when the

   * corresponding keys.
   */
  @Override
  public ImmutableCollection<V> values() {
    return valueList;
  }

  @Override
  ImmutableCollection<V> createValues() {
    throw new AssertionError("should never be called");
  }

  /**
   * Returns the comparator that orders the keys, which is {@link Ordering#natural()} when the