public final Version version() {
   final Data data = data();
   return (data == null ? null : data.version());
 }
 public final String versioned() {
   final Data data = data();
   return (data == null ? null : data.versioned());
 }
 public final boolean compatible() {
   final Data data = data();
   return (data == null ? true : data.compatible());
 }