class Bag extends AbstractCollection<T> implements Serializable {

    public Bag<T> createSorted(Order order) {
        Validate.notNull(order, "order must not be null");
        Map<T, Integer> sorted = CollectionHelper.sortByValue(map, order);
        return new Bag<>(sorted, size);
    }

    public  Bag();
    public  Bag(Map<? extends T, ? extends Integer> map);
    private  Bag(Map<T, Integer> map, int size);
    public  Bag(Iterable<? extends T> iterable);

}