anchor.diff:  
       if (elt >= 0x10 && elt <= 0xFF)
         nextCode = _readPCreators(group, code, isExplicitVR, pg);
  +    log.debug('subgroups: ${pg.subgroups}');
   
       // Read the PrivateData
       if (Group.fromTag(nextCode) == group)
         _readAllPData(group, nextCode, isExplicitVR, pg);
   
  -    log.debug('$ree readPrivateGroup-end $pg');
  +    log.debug('$ree _readPrivateGroup-end $pg');
       log.up;
       return pg;
     }
  
positive.code:     //?? while (pcTag.isValidDataCode(nextCode)) {
      PrivateCreator pc = sg.creator;
      PrivateCreatorTag pcTag = pc.tag;
      while (pc.inSubgroup(nextCode)) {
        log.down;
        log.debug('$rbb readPData: base(${Elt.hex(pc.base)}), '
            'limit(${Elt.hex(pc.limit)})');
  
        PrivateDataTag dTag = pcTag.lookupData(code);
        Element e = _readElement(dTag, isExplicitVR);
        pc.add(e);
        currentDS.add(e);
  
        log.debug('$rmm readPD: ${e.info})');
        log.up;
        nextCode = _peekTagCode();
      }
      return nextCode;
    }
  
negative.code:   void _readAllPData(int group, int code, bool isExplicitVR, PrivateGroup pg) {
      // Now read the [PrivateData] [Element]s for each creator, in order.
      log.down;
      log.debug('$rbb _readAllPData');
      int nextCode = code;
      while (group == Group.fromTag(nextCode)) {
        log.debug('nextCode: ${Tag.toDcm(nextCode)}');
        var sgIndex = Elt.fromTag(nextCode) >> 8;
        log.debug('sgIndex: $sgIndex');
        var sg = pg[sgIndex];
        log.debug('Subgroup: $sg');
        if (sg == null) {
          log.warn('This is a Subgroup without a creator');
          sg = new PrivateSubGroup(pg, PrivateCreator.kNonExtantCreator);
        }
        log.debug('Subgroup: $sg');
        nextCode = _readPDSubgroup(nextCode, isExplicitVR, sg);
        log.debug('Subgroup: $sg');
        log.debug('nextCode: nextCode');
      }
      log.debug('$ree _readAllPData-end');
      log.up;
    }
  
  