code: protected TimeZone fetchTimeZone(final String id) throws TimezonesException {
      final TaggedTimeZone ttz = fetchTimeZone(id, null);
  
      if (ttz == null) {
        return null;
      }
  
      register(id, ttz.tz);
  
      return ttz.tz;
    }
docs: Fetch a timezone object from the server given the id.
  
  @param id the tzid
  @return TimeZone with id or null
  @throws TimezonesException on error