Patch# 1258 by Christian Heimes: kill basestring.
I like this because it makes the code shorter! :-)
diff --git a/Lib/pickle.py b/Lib/pickle.py
index 45e7a8e..18ad210 100644
--- a/Lib/pickle.py
+++ b/Lib/pickle.py
@@ -307,7 +307,7 @@
                                         (t.__name__, obj))
 
         # Check for string returned by reduce(), meaning "save as global"
-        if isinstance(rv, basestring):
+        if isinstance(rv, str):
             self.save_global(obj, rv)
             return