private Object handleVers(Object tos) {
      if ((tos instanceof Generator && ((Generator)tos).getVersion() == null) ||
          (tos instanceof GedcomVersion && ((GedcomVersion)tos).getVersion() == null) ||
          (tos instanceof CharacterSet && ((CharacterSet)tos).getVersion() == null)) {
         return new FieldRef(tos, "Version");
      }
      return null;
   }