class Bag extends AbstractCollection<T> implements Serializable {

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null || getClass() != obj.getClass()) {
            return false;
        }
        Bag<?> other = (Bag<?>)obj;
        if (size != other.size) {
            return false;
        }
        return map.equals(other.map);
    }

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

}