public static HashSetMultiDictionary <TKey, TValue> Of(TKey key1, TValue value1, TKey key2, TValue value2)
        {
            var result = new HashSetMultiDictionary <TKey, TValue>();

            result.Put(key1, value1);
            result.Put(key2, value2);
            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, TKey key8, TValue value8,
                                                               TKey key9, TValue value9, TKey key10, TValue value10)
        {
            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);
            result.Put(key8, value8);
            result.Put(key9, value9);
            result.Put(key10, value10);
            return(result);
        }