*
   * @param sets the sets to choose elements from, in the order that the elements chosen from those
   *     sets should appear in the resulting lists
   * @param <B> any common base class shared by all axes (often just {@link Object})
   * @return the Cartesian product, as an immutable set containing immutable lists
   * @throws NullPointerException if {@code sets}, any one of the {@code sets}, or any element of a

   * Returns an iterator containing the elements of {@code array} in order. The returned iterator is
   * a view of the array; subsequent changes to the array will be reflected in the iterator.
   *
   * <p><b>Note:</b> It is often preferable to represent your data using a collection type, for
   * example using {@link Arrays#asList(Object[])}, making this method unnecessary.
   *