Allow list sort's comparison function to explicitly be None.  See SF patch
661092.
diff --git a/Misc/NEWS b/Misc/NEWS
index e786af5..b9c076d 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@
 Core and builtins
 -----------------
 
+- List objects' sort() method now accepts None as the comparison function.
+  Passing None is semantically identical to calling sort() with no
+  arguments.
+
 Extension modules
 -----------------