code: public static <E extends OrdinalValue<E>> ImmutableOrdinalSet<E> copyOf(E[] elements) {
      return constructFromArray(elements);
    }
docs: Creates immutable ordinal set from array of elements.
  All elements expected to have same {@link OrdinalValue#domain()} as the first element,
  otherwise exception will be thrown.
  @param <E> the element type
  @param elements the elements, no nulls allowed
  @return the immutable ordinal set