Add mktime_tz to __all__.  It's documented as being available in email.utils.
diff --git a/Lib/email/utils.py b/Lib/email/utils.py
index 50010e6..87979dc 100644
--- a/Lib/email/utils.py
+++ b/Lib/email/utils.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2001-2006 Python Software Foundation
+# Copyright (C) 2001-2009 Python Software Foundation
 # Author: Barry Warsaw
 # Contact: email-sig@python.org
 
@@ -13,6 +13,7 @@
     'formatdate',
     'getaddresses',
     'make_msgid',
+    'mktime_tz',
     'parseaddr',
     'parsedate',
     'parsedate_tz',