Add python_requires to help pip
diff --git a/setup.py b/setup.py
index 5f727ae..6154ba7 100755
--- a/setup.py
+++ b/setup.py
@@ -3,4 +3,5 @@
 
 setuptools.setup(
     setup_requires=['pbr>=1.3', 'setuptools>=17.1'],
+    python_requires='>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*',
     pbr=True)