diff -r b7d13b2ad67e -r 1fd6814a29fc backup.py
--- a/backup.py	Wed Jan 24 22:04:16 2018 +0000
+++ b/backup.py	Wed Jan 24 22:23:51 2018 +0000
@@ -65,7 +65,7 @@
     def __init__(self, backup, op=None):
         if op:
             super().__init__(op.operation, op.when_monotonic,
-                             detail=op.detail)
+                             **op.detail)
         else:
             super().__init__(None, None)