code: func GetPodSource(pod *v1.Pod) (string, error) {
  	if pod.Annotations != nil {
  		if source, ok := pod.Annotations[ConfigSourceAnnotationKey]; ok {
  			return source, nil
  		}
  	}
  	return "", fmt.Errorf("cannot get source of pod %q", pod.UID)
  }
docs: // GetPodSource returns the source of the pod based on the annotation.