code: func resourceVSphereDatastoreClusterValidateEmptyCluster(d structure.ResourceIDStringer, pod *object.StoragePod) error {
  	log.Printf("[DEBUG] %s: Checking to ensure that datastore cluster is empty", resourceVSphereDatastoreClusterIDString(d))
  	ne, err := storagepod.HasChildren(pod)
  	if err != nil {
  		return fmt.Errorf("error checking for datastore cluster contents: %s", err)
  	}
  	if ne {
  		return fmt.Errorf(
  			"datastore cluster %q still has datastores. Please move or remove all datastores before deleting",
  			pod.InventoryPath,
  		)
  	}
  	return nil
  }
docs: // resourceVSphereDatastoreClusterValidateEmptyCluster validates that the
  // datastore cluster is empty. This is used to ensure a safe deletion of the
  // cluster - we do not allow deletion of clusters that still have datastores in
  // them.