protected bool Equals(Punctuation other)
 {
     return string.Equals(Chars, other.Chars) &&
         IsSentencesSeparator == other.IsSentencesSeparator &&
         IsSyntacticConstructionsSeparator == other.IsSyntacticConstructionsSeparator;
 }
 protected Punctuation(Punctuation clone)
 {
     Chars = clone.Chars;
     IsSentencesSeparator = clone.IsSentencesSeparator;
     IsSyntacticConstructionsSeparator = clone.IsSyntacticConstructionsSeparator;
 }