'Creates a snapshot.
:param snapshot: The Cinder snapshot
:param group_name: An optional label for the snapshot group
:returns: An E-Series snapshot image'

def create_snapshot(self, snapshot):

    os_vol = snapshot['volume']
    vol = self._get_volume(os_vol['name_id'])
    snap_image = cinder_utils.synchronized(vol['id'])(self._create_es_snapshot)(vol)
    model_update = {'provider_id': snap_image['id']}
    return model_update
