class MultiMap extends HashMap<String, List<V>> {

    public List<V> put(String name, V value) {
        if (value == null) {
            return super.put(name, null);
        }
        List<V> vals = new ArrayList<>();
        vals.add(value);
        return put(name, vals);
    }

    public  MultiMap();
    public  MultiMap(Map<String, List<V>> map);
    public  MultiMap(MultiMap<V> map);

}