code: func GetPersistentVolumeClass(volume *v1.PersistentVolume) string {
  	// Use beta annotation first
  	if class, found := volume.Annotations[v1.BetaStorageClassAnnotation]; found {
  		return class
  	}
  
  	return volume.Spec.StorageClassName
  }
docs: // GetPersistentVolumeClass returns StorageClassName.