code: public static <E extends Comparable<? super E>> ImmutableSortedSet<E> copyOf(E[] elements) {
      return construct(Ordering.natural(), elements.length, elements.clone());
    }
docs: Returns an immutable sorted set containing the given elements sorted by their natural ordering.
  When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
  one specified is included.
  
  @throws NullPointerException if any of {@code elements} is null
  @since 3.0