* @return the XML datetime string corresponding to the given CycL date
   * @deprecated use DateConverter.
   */
  static public String xmlDatetimeString(final CycList date) throws IOException, CycApiException {
    try {
      final CycNaut dateNaut = (CycNaut) CycNaut.convertIfPromising(date);
      final Date javadate = DateConverter.parseCycDate(dateNaut, TimeZone.getDefault(), false);
      int cycDatePrecision = DateConverter.getCycDatePrecision(dateNaut);
      if (cycDatePrecision > DateConverter.DAY_GRANULARITY) {
        return new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'").format(javadate);
      } else {
        return new SimpleDateFormat("yyyy-MM-dd").format(javadate);
      }
    } catch (Exception e) {
      return null;
    }
  }