Object writeReplace() {
              return super.writeReplace();
            }
          };
      return new CartesianSet<E>(axes, new CartesianList<E>(listAxes));
    }

    private CartesianSet(ImmutableList<ImmutableSet<E>> axes, CartesianList<E> delegate) {
      this.axes = axes;
      this.delegate = delegate;
    }

    @Override
    protected Collection<List<E>> delegate() {

   *     a provided list is null
   * @since 19.0
   */
  public static <B> List<List<B>> cartesianProduct(List<? extends List<? extends B>> lists) {
    return CartesianList.create(lists);
  }

  /**
   * Returns every possible list that can be formed by choosing one element from each of the given