code: func (pvcr *persistentVolumeClaimResize) allowResize(pvc, oldPvc *api.PersistentVolumeClaim) bool {
  	pvcStorageClass := apihelper.GetPersistentVolumeClaimClass(pvc)
  	oldPvcStorageClass := apihelper.GetPersistentVolumeClaimClass(oldPvc)
  	if pvcStorageClass == "" || oldPvcStorageClass == "" || pvcStorageClass != oldPvcStorageClass {
  		return false
  	}
  	sc, err := pvcr.scLister.Get(pvcStorageClass)
  	if err != nil {
  		return false
  	}
  	if sc.AllowVolumeExpansion != nil {
  		return *sc.AllowVolumeExpansion
  	}
  	return false
  }
docs: // Growing Persistent volumes is only allowed for PVCs for which their StorageClass
  // explicitly allows it.