Hide list comp variables and support set comprehensions
diff --git a/Lib/test/test_datetime.py b/Lib/test/test_datetime.py
index 6b4c667..8a7c1b6 100644
--- a/Lib/test/test_datetime.py
+++ b/Lib/test/test_datetime.py
@@ -20,9 +20,9 @@
 from datetime import date, datetime
 
 pickle_choices = [(pickler, unpickler, proto)
-                  for pickler in pickle, cPickle
+                  for pickler in (pickle, cPickle)
                   if pickler is not None
-                  for unpickler in pickle, cPickle
+                  for unpickler in (pickle, cPickle)
                   if unpickler is not None
                   for proto in range(3)]
 if cPickle is None: