class Elements implements List<Element>, Cloneable {

    public Elements eq(int index) {
        return contents.size() > index ? new Elements(get(index)) : new Elements();
    }

    public  Elements();
    public  Elements(int initialCapacity);
    public  Elements(Collection<Element> elements);
    public  Elements(List<Element> elements);
    public  Elements(Element... elements);

}