code: func PersistentVolumeClaimHasClass(claim *core.PersistentVolumeClaim) bool {
  	// Use beta annotation first
  	if _, found := claim.Annotations[core.BetaStorageClassAnnotation]; found {
  		return true
  	}
  
  	if claim.Spec.StorageClassName != nil {
  		return true
  	}
  
  	return false
  }
docs: // PersistentVolumeClaimHasClass returns true if given claim has set StorageClassName field.