@Nullable
  public static Collection<XmlFile> getDependencies(XmlFile element) {
    final CommonProcessors.CollectUniquesProcessor<XmlFile> processor = new CommonProcessors.CollectUniquesProcessor<>() {
      @Override
      public boolean process(XmlFile file) {
        if (!getResults().contains(file)) {
          XsltIncludeIndex.processForwardDependencies(file, this);
        }
        return super.process(file);
      }
    };
    XsltIncludeIndex.processForwardDependencies(element, processor);
    return processor.getResults();
  }
@Nullable
  public static Collection<XmlFile> getDependencies(XmlFile element)