If one is going to mark scripts executable, one had best add a shebang line...

setup.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 from distutils.core import setup
 
 setup(

test_contextlib2.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """Unit tests for contextlib.py, and other context managers."""
 
 import sys