private FileGroup createOrGet(final Parent possibleParent, final FileGroup fromGroup) {
    FileGroup ownGroup = myGroupHolder.get(fromGroup.getId());
    if (ownGroup == null) {
      ownGroup = new FileGroup(fromGroup.getUpdateName(), fromGroup.getStatusName(), fromGroup.getSupportsDeletion(),
                               fromGroup.getId(), fromGroup.myCanBeAbsent);
      possibleParent.accept(ownGroup);
      myGroupHolder.put(fromGroup.getId(), ownGroup);
    }
    return ownGroup;
  }
private FileGroup createOrGet(final Parent possibleParent, final FileGroup fromGroup)