public static int Max(this MySet set)
        {
            int len = set.GetItemByIndex(0).Length;

            foreach (string item in set.GetHash())
            {
                if (len < item.Length)
                {
                    len = item.Length;
                }
            }
            return(len);
        }
        public static void CommaAfterWord(this MySet set)
        {
            int len = set.GetSize();
            HashSet <string> res = new HashSet <string>();
            string           buf = "";

            for (int i = 0; i < len; i++)
            {
                buf = set.GetItemByIndex(i);
                res.Add(buf);
                res.Add(",");
            }
            //foreach (string item in res)
            //{
            //    Console.WriteLine(item);
            //}
            set.collection = res;
        }