public void rawAddChildrenWithoutNotifications(@NotNull TreeElement first) {
    TreeElement last = getLastChildNode();
    if (last == null){
      TreeElement chainLast = rawSetParents(first, this);
      setFirstChildNode(first);
      setLastChildNode(chainLast);
    }
    else {
      last.rawInsertAfterMeWithoutNotifications(first);
    }

    DebugUtil.checkTreeStructure(this);
  }
public void rawAddChildrenWithoutNotifications(@NotNull TreeElement first)