code: func (g *Cloud) DeleteDisk(diskToDelete string) error {
  	err := g.doDeleteDisk(diskToDelete)
  	if isGCEError(err, "resourceInUseByAnotherResource") {
  		return volerr.NewDeletedVolumeInUseError(err.Error())
  	}
  
  	if err == cloudprovider.DiskNotFound {
  		return nil
  	}
  	return err
  }
docs: // DeleteDisk deletes rgw referenced persistent disk.