--- a/mercurial/subrepo.py	Sun Sep 26 16:01:13 2010 -0500
+++ b/mercurial/subrepo.py	Sun Sep 26 16:11:04 2010 -0500
@@ -220,7 +220,7 @@
         """
         raise NotImplementedError
 
-    def checknested(path):
+    def checknested(self, path):
         """check if path is a subrepository within this repository"""
         return False