code: public static <E> List<E> of(E e1, E e2, E e3, E e4) {
      List<E> list = new ArrayList<>();
      list.add(e1);
      list.add(e2);
      list.add(e3);
      list.add(e4);
      return list;
    }
docs: Returns a list of the given elements, in order.