code: func isRegionalPD(spec *volume.Spec) bool {
  	if spec.PersistentVolume != nil {
  		zonesLabel := spec.PersistentVolume.Labels[v1.LabelZoneFailureDomain]
  		zones := strings.Split(zonesLabel, cloudvolume.LabelMultiZoneDelimiter)
  		return len(zones) > 1
  	}
  	return false
  }
docs: // Checks whether the given GCE PD volume spec is associated with a regional PD.