Index: root/xen-unstable.hg/tools/python/xen/xend/XendAPI.py
===================================================================
--- root.orig/xen-unstable.hg/tools/python/xen/xend/XendAPI.py
+++ root/xen-unstable.hg/tools/python/xen/xend/XendAPI.py
@@ -555,7 +555,7 @@ class XendAPI(object):
                 return xen_api_success(ref)
 
             def unpack(v):
-                return v['Value']
+                return v.get('Value')
 
             def _get_all_records(_api_cls):
                 return lambda s, session: \