class Sets {

  /**
   * Creates a <em>mutable</em> {@link LinkedHashSet} containing the given elements.
   *
   * @param <T> the generic type of the {@code HashSet} to create.
   * @param elements the elements to store in the {@code HashSet}.
   * @return the created {@code HashSet}, or {@code null} if the given array of elements is {@code null}.
   */
  @SafeVarargs
  public static <T> Set<T> set(T... elements) {
    return newLinkedHashSet(elements);
  }

  /**
   * Creates a <em>mutable</em> {@code HashSet}.
   *
   * @param <T> the generic type of the {@code HashSet} to create.
   * @return the created {@code HashSet}.
   */
  public static <T> HashSet<T> newHashSet() {
    return new HashSet<>();
  }

  /**
   * Creates a <em>mutable</em> {@code HashSet} containing the given elements.
   *
   * @param <T> the generic type of the {@code HashSet} to create.
   * @param elements the elements to store in the {@code HashSet}.
   * @return the created {@code HashSet}, or {@code null} if the given array of elements is {@code null}.
   */
  public static <T> HashSet<T> newHashSet(Iterable<? extends T> elements) {<FILL_FUNCTION_BODY>}

  /**
   * Creates a <em>mutable</em> {@code LinkedHashSet}.
   *
   * @param <T> the generic type of the {@code LinkedHashSet} to create.
   * @return the created {@code LinkedHashSet}.
   */
  public static <T> LinkedHashSet<T> newLinkedHashSet() {
    return new LinkedHashSet<>();
  }

  /**
   * Creates a <em>mutable</em> {@link LinkedHashSet} containing the given elements.
   *
   * @param <T> the generic type of the {@code LinkedHashSet} to create.
   * @param elements the elements to store in the {@code LinkedHashSet}.
   * @return the created {@code LinkedHashSet}, or {@code null} if the given array of elements is {@code null}.
   */
  @SafeVarargs
  public static <T> LinkedHashSet<T> newLinkedHashSet(T... elements) {
    if (elements == null) {
      return null;
    }
    LinkedHashSet<T> set = newLinkedHashSet();
    java.util.Collections.addAll(set, elements);
    return set;
  }

  /**
   * Creates a <em>mutable</em> {@link TreeSet}.
   *
   * @param <T> the generic type of the {@link TreeSet} to create.
   * @return the created {@link TreeSet}.
   */
  public static <T> TreeSet<T> newTreeSet() {
    return new TreeSet<>();
  }

  /**
   * Creates a <em>mutable</em> {@link TreeSet} containing the given elements.
   *
   * @param <T> the generic type of the {@link TreeSet} to create.
   * @param elements the elements to store in the {@link TreeSet}.
   * @return the created {@link TreeSet}, or {@code null} if the given array of elements is {@code null}.
   */
  @SafeVarargs
  public static <T> TreeSet<T> newTreeSet(T... elements) {
    if (elements == null) {
      return null;
    }
    TreeSet<T> set = newTreeSet();
    java.util.Collections.addAll(set, elements);
    return set;
  }

  private Sets() {}
}

    if (elements == null) {
      return null;
    }
    return Streams.stream(elements).collect(toCollection(HashSet::new));
  
<no_super_class>