diff --git a/tempest/scenario/test_stamp_pattern.py b/tempest/scenario/test_stamp_pattern.py
index cfc1d37..e59858b 100644
--- a/tempest/scenario/test_stamp_pattern.py
+++ b/tempest/scenario/test_stamp_pattern.py
@@ -101,7 +101,7 @@
 
     def _attach_volume(self, server, volume):
         # TODO(andreaf) we should use device from config instead if vdb
-        _, attached_volume = self.servers_client.attach_volume(
+        attached_volume = self.servers_client.attach_volume(
             server['id'], volume['id'], device='/dev/vdb')
         self.assertEqual(volume['id'], attached_volume['id'])
         self._wait_for_volume_status(attached_volume, 'in-use')