private void addRendererIfNotDefault(@NotNull Renderer renderer, @NotNull Element to) {
    Element element = writeRenderer(renderer);
    if (element.getContentSize() == 0 && element.getAttributes().size() <= 1 /* ID attribute */) {
      return;
    }

    to.addContent(element);
  }
private void addRendererIfNotDefault(@NotNull Renderer renderer, @NotNull Element to)