@Override
  public void writeExternal(@NotNull Element element) throws WriteExternalException {
    List<Element> toWrite = null;
    for (OrderRootType orderRootType : myOrderRootPointerContainers.keySet()) {
      VirtualFilePointerContainer container = myOrderRootPointerContainers.get(orderRootType);
      if (container != null && container.size() > 0) {
        final Element content = new Element(((PersistentOrderRootType)orderRootType).getModulePathsName());
        container.writeExternal(content, ROOT_ELEMENT, false);
        if (toWrite == null) {
          toWrite = new ArrayList<>();
        }
        toWrite.add(content);
      }
    }
    if (toWrite != null) {
      toWrite.sort(Comparator.comparing(Element::getName));
      for (Element content : toWrite) {
        element.addContent(content);
      }
    }
  }
@Override
  public void writeExternal(@NotNull Element element)