code: func FilterReplicaSets(RSes []*apps.ReplicaSet, filterFn filterRS) []*apps.ReplicaSet {
  	var filtered []*apps.ReplicaSet
  	for i := range RSes {
  		if filterFn(RSes[i]) {
  			filtered = append(filtered, RSes[i])
  		}
  	}
  	return filtered
  }
docs: // FilterReplicaSets returns replica sets that are filtered by filterFn (all returned ones should match filterFn).