Enhance issubclass() and PyObject_IsSubclass() so that a tuple is
supported as the second argument. This has the same meaning as
for isinstance(), i.e. issubclass(X, (A, B)) is equivalent
to issubclass(X, A) or issubclass(X, B). Compared to isinstance(),
this patch does not search the tuple recursively for classes, i.e.
any entry in the tuple that is not a class, will result in a
TypeError.

This closes SF patch #649608.
diff --git a/Misc/NEWS b/Misc/NEWS
index 033c5c8..d51ddbb 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -84,6 +84,10 @@
 Core and builtins
 -----------------
 
+- issubclass now supports a tuple as the second argument, just like
+  isinstance does. ``issubclass(X, (A, B))`` is equivalent to
+  ``issubclass(X, A) or issubclass(X, B)``.
+
 - Thanks to Armin Rigo, the last known way to provoke a system crash
   by cleverly arranging for a comparison function to mutate a list
   during a list.sort() operation has been fixed.  The effect of