@Override
  protected FoldingBuilder findForLanguage(@NotNull Language l) {
    List<FoldingBuilder> extensions = allForLanguage(l);
    if (extensions.isEmpty()) {
      return null;
    }
    else if (extensions.size() == 1) {
      return extensions.get(0);
    }
    else {
      return new CompositeFoldingBuilder(extensions);
    }
  }
@Override
  protected FoldingBuilder findForLanguage(@NotNull Language l)