diff -r d739f423bf06 -r 1a184b727aff contrib/python-hook-examples.py
--- a/contrib/python-hook-examples.py	Wed Sep 26 22:17:34 2018 -0700
+++ b/contrib/python-hook-examples.py	Wed Sep 26 10:38:37 2018 -0700
@@ -19,7 +19,7 @@
     node = kwargs['node']
     first = repo[node].p1().node()
     if 'url' in kwargs:
-        last = repo['tip'].node()
+        last = repo.changelog.tip()
     else:
         last = node
     diff = patch.diff(repo, first, last)