class PropertyValue implements Serializable, Iterable<PropertyValue> {

    public Map<String,String> toLocalMap(){
        Map<String, String> map = new TreeMap<>();
        if(value!=null) {
            map.put(getKey(), value);
        }
        return map;
    }

    public  PropertyValue(String key);
    protected  PropertyValue(String key, String value);

}