SF 952807:  Unpickling pickled instances of subclasses of datetime.date,
datetime.datetime and datetime.time could yield insane objects.  Thanks
to Jiwon Seo for the fix.

Bugfix candidate.  I'll backport it to 2.3.
diff --git a/Misc/NEWS b/Misc/NEWS
index fe6df61..cfd296e 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@
 Core and builtins
 -----------------
 
+- Bug #952807:  Unpickling pickled instances of subclasses of
+  datetime.date, datetime.datetime and datetime.time could yield insane
+  objects.  Thanks to Jiwon Seo for a fix.
+
 - Bug #845802: Python crashes when __init__.py is a directory.
 
 - Unicode objects received two new methods: iswide() and width().