'Get the most recent backup snapshot of the provided image.
Returns name of most recent backup snapshot or None if there are no
backup snapshots.'

def _get_most_recent_snap(self, rbd_image):

    backup_snaps = self.get_backup_snaps(rbd_image, sort=True)
    if (not backup_snaps):
        return None
    return backup_snaps[0]['name']
