@Override
    public int compare(final Element o1, final Element o2) {
      for (String attribName : COMPARABLE_ATTRIB_NAMES) {
        final int valuesEqual = Comparing.compare(o1.getAttributeValue(attribName), o2.getAttributeValue(attribName));
        if (valuesEqual != 0) {
          return valuesEqual;
        }
      }
      return 0;
    }
@Override
    public int compare(final Element o1, final Element o2)