docs: public org.w3c.dom.Document outputW3CDom(final WireFeed feed) throws IllegalArgumentException, FeedException {
          final Document doc = outputJDom(feed);
          final DOMOutputter outputter = new DOMOutputter();
          try {
              return outputter.output(doc);
          } catch (final JDOMException jdomEx) {
              throw new FeedException("Could not create DOM", jdomEx);
          }
      }