code: async def get_zones(self) -> List[Zone]:
          
          res = await self.services["avContent"]["getCurrentExternalTerminalsStatus"]()
          zones = [Zone.make(services=self.services, **x) for x in res if 'meta:zone:output' in x['meta']]
          if not zones:
              raise SongpalException("Device has no zones")
          return zones
docs: Return list of available zones.