code: def get_ituz(self, callsign, timestamp=timestamp_now):
          
          return self.get_all(callsign, timestamp)[const.ITUZ]
docs: Returns ITU Zone of a callsign
  
          Args:
              callsign (str): Amateur Radio callsign
              timestamp (datetime, optional): datetime in UTC (tzinfo=pytz.UTC)
  
          Returns:
              int: containing the callsign's CQ Zone
  
          Raises:
              KeyError: No ITU Zone found for callsign
  
          Note:
              Currently, only Country-files.com lookup database contains ITU Zones