*
   * @return a new, empty {@code LinkedHashSet}
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
  public static <E extends @Nullable Object> LinkedHashSet<E> newLinkedHashSet() {
    return new LinkedHashSet<>();
  }

  /**
   * Creates a <i>mutable</i> {@code LinkedHashSet} instance containing the given elements in order.
   *

   *
   * @return a new, empty {@code LinkedHashSet}
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
  public static <E extends @Nullable Object> LinkedHashSet<E> newLinkedHashSet() {
    return new LinkedHashSet<>();
  }

  /**
   * Creates a <i>mutable</i> {@code LinkedHashSet} instance containing the given elements in order.
   *

    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);
    }
    Set<List<Optional<?>>> cartesianProduct = Sets.cartesianProduct(optionalSets);

    addAll(list, elements);
    return list;
  }

  public static <E extends @Nullable Object> List<E> copyToList(E[] elements) {
    return copyToList(asList(elements));
  }

  // Clone of Sets.newLinkedHashSet
  public static <E extends @Nullable Object> Set<E> copyToSet(Iterable<? extends E> elements) {
    Set<E> set = new LinkedHashSet<>();
    addAll(set, elements);
    return set;
  }

    addAll(list, elements);
    return list;
  }

  public static <E extends @Nullable Object> List<E> copyToList(E[] elements) {
    return copyToList(asList(elements));
  }

  // Clone of Sets.newLinkedHashSet
  public static <E extends @Nullable Object> Set<E> copyToSet(Iterable<? extends E> elements) {
    Set<E> set = new LinkedHashSet<>();
    addAll(set, elements);
    return set;
  }