public static HashSetMultiDictionary <TKey, TValue> Of(TKey key, TValue value)
        {
            var result = new HashSetMultiDictionary <TKey, TValue>();

            result.Put(key, value);
            return(result);
        }
        public static HashSetMultiDictionary <TKey, TValue> Of(TKey key1, TValue value1, TKey key2, TValue value2, TKey key3, TValue value3)
        {
            var result = new HashSetMultiDictionary <TKey, TValue>();

            result.Put(key1, value1);
            result.Put(key2, value2);
            result.Put(key3, value3);
            return(result);
        }
        public static HashSetMultiDictionary <TKey, TValue> Of(TKey key1, TValue value1, TKey key2, TValue value2, TKey key3, TValue value3,
                                                               TKey key4, TValue value4, TKey key5, TValue value5, TKey key6, TValue value6, TKey key7, TValue value7)
        {
            var result = new HashSetMultiDictionary <TKey, TValue>();

            result.Put(key1, value1);
            result.Put(key2, value2);
            result.Put(key3, value3);
            result.Put(key4, value4);
            result.Put(key5, value5);
            result.Put(key6, value6);
            result.Put(key7, value7);
            return(result);
        }