docs: def handle_features(self, device_features):
          """Handles features of the device"""
  
          self.device_features = device_features
  
          if device_features and 'zone' in device_features:
              for zone in device_features['zone']:
                  zone_id = zone.get('id')
                  if zone_id in self.zones:
                      _LOGGER.debug("handle_features: %s", zone_id)
                      input_list = zone.get('input_list', [])
                      input_list.sort()
                      self.zones[zone_id].source_list = input_list