public void characterData(CMLStack xpath, char ch[], int start, int length) {
   String s = new String(ch, start, length).trim();
   if (xpath.toString().endsWith("string/") && BUILTIN.equals("stereo")) {
     stereoGiven = true;
     if (s.trim().equals("W")) {
       logger.debug("CML W stereo found");
       bondStereo.add("1");
     } else if (s.trim().equals("H")) {
       logger.debug("CML H stereo found");
       bondStereo.add("6");
     }
   } else {
     super.characterData(xpath, ch, start, length);
   }
 }