code: func (s *PresenceService) GetRemoteClusters(opts ...services.MarshalOption) ([]services.RemoteCluster, error) {
  	startKey := backend.Key(remoteClustersPrefix)
  	result, err := s.GetRange(context.TODO(), startKey, backend.RangeEnd(startKey), backend.NoLimit)
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  
  	clusters := make([]services.RemoteCluster, len(result.Items))
  	for i, item := range result.Items {
  		cluster, err := services.UnmarshalRemoteCluster(item.Value,
  			services.AddOptions(opts, services.WithResourceID(item.ID), services.WithExpires(item.Expires))...)
  		if err != nil {
  			return nil, trace.Wrap(err)
  		}
  		clusters[i] = cluster
  	}
  	return clusters, nil
  }
docs: // GetRemoteClusters returns a list of remote clusters