docs: public String outputString(final WireFeed feed, final boolean prettyPrint) throws IllegalArgumentException, FeedException {
          final Document doc = outputJDom(feed);
          final String encoding = feed.getEncoding();
          Format format;
          if (prettyPrint) {
              format = Format.getPrettyFormat();
          } else {
              format = Format.getCompactFormat();
          }
          if (encoding != null) {
              format.setEncoding(encoding);
          }
          final XMLOutputter outputter = new XMLOutputter(format);
          return outputter.outputString(doc);
      }