--- a/utils.py	Thu Apr 30 13:08:11 2009 +0200
+++ b/utils.py	Thu Apr 30 14:17:22 2009 +0200
@@ -27,7 +27,7 @@
     """return a date from a date (leaving unchanged) or a datetime"""
     if isinstance(somedate, datetime):
         return date(somedate.year, somedate.month, somedate.day)
-    assert isinstance(somedate, date)
+    assert isinstance(somedate, date), repr(somedate)
     return date
 
 ONEDAY = timedelta(days=1)