code: def time_zone_by_addr(self, addr):
          
          if self._databaseType not in const.CITY_EDITIONS:
              message = 'Invalid database type, expected City'
              raise GeoIPError(message)
  
          ipnum = util.ip2long(addr)
          return self._get_record(ipnum).get('time_zone')
docs: Returns time zone in tzdata format (e.g. America/New_York or Europe/Paris)
  
          :arg addr: IP address (e.g. 203.0.113.30)