code: def _get_existing(driver, zone_name, server_name, validation):
      
      if zone_name is None:
          zones = sorted(
              (z for z
               in driver.list_zones()
               if server_name.rstrip(u'.')
                  .endswith(u'.' + z.domain.rstrip(u'.'))),
              key=lambda z: len(z.domain),
              reverse=True)
          if len(zones) == 0:
              raise NotInZone(server_name=server_name, zone_name=None)
      else:
          zones = [
              z for z
              in driver.list_zones()
              if z.domain == zone_name]
          if len(zones) == 0:
              raise ZoneNotFound(zone_name=zone_name)
      zone = zones[0]
      subdomain = _split_zone(server_name, zone.domain)
      existing = [
          record for record
          in zone.list_records()
          if record.name == subdomain and
          record.type == 'TXT' and
          record.data == validation]
      return zone, existing, subdomain
docs: Get existing validation records.