docs: def _clear_expired_zones(self):
          """
          Update zone status for all expired zones.
          """
          zones = []
  
          for z in list(self._zones.keys()):
              zones += [z]
  
          for z in zones:
              if self._zones[z].status != Zone.CLEAR and self._zone_expired(z):
                  self._update_zone(z, Zone.CLEAR)