'Remove a snapshot image from the storage backend
If a snapshot group has no remaining snapshot images associated with
it, it will be deleted as well. When the snapshot is deleted,
any snapshot volumes that are associated with it will be orphaned,
so they are also deleted.
:param es_snapshot: An E-Series snapshot image
:param snapshot_volumes: Snapshot volumes associated with the snapshot'

def _delete_snapshot_image(self, es_snapshot):

    self._client.delete_snapshot_image(es_snapshot['id'])
