--- a/devtools/testlib.py	Fri Sep 11 16:01:10 2015 +0200
+++ b/devtools/testlib.py	Tue Sep 15 15:10:59 2015 +0200
@@ -28,7 +28,6 @@
 from math import log
 from contextlib import contextmanager
 from warnings import warn
-from types import NoneType
 from itertools import chain
 
 import yams.schema