'Find a E-Series snapshot by the name of the snapshot group.
Snapshots were previously identified by the unique name of the
snapshot group. A snapshot volume is now utilized to uniquely
identify the snapshot, so any snapshots previously defined in this
way must be updated.
:param snapshot_id: Cinder snapshot identifer
:return: An E-Series snapshot image'

def _get_snapshot_legacy(self, snapshot):

    label = utils.convert_uuid_to_es_fmt(snapshot['id'])
    for group in self._client.list_snapshot_groups():
        if (group['label'] == label):
            image = self._get_oldest_image_in_snapshot_group(group['id'])
            group_label = utils.convert_uuid_to_es_fmt(uuid.uuid4())
            self._client.update_snapshot_group(group['id'], group_label)
            snapshot.update({'provider_id': image['id']})
            snapshot.save()
            return image
    raise exception.NotFound((_('Snapshot    with    id    of    %s    could    not    be    found.') % snapshot['id']))
