code: def flush_zone(cls, zone_name):
          '''Flushes the zone cache, if there is one'''
          cls.log.debug('flush_zone: zone_name=%s', zone_name)
          try:
              del cls._cache[zone_name]
          except KeyError:
              pasf flush_zone(cls, zone_name):
          '''Flushes the zone cache, if there is one'''
          cls.log.debug('flush_zone: zone_name=%s', zone_name)
          try:
              del cls._cache[zone_name]
          except KeyError:
              pass
docs: Flushes the zone cache, if there is one