public void RemoveWord(string word)
 {
     if (!AddedWords.Remove(word))
     {
         return;
     }
     AvailableWordList.Add(word);
 }
 public void SetRange(IEnumerable <string> range)
 {
     AddedWords        = range.ToList();
     AvailableWordList = new SortedSet <string>(AvailableWordList.Except(range));
 }