diff --git a/tox.ini b/tox.ini
index 8ba8fab..ecb9aa1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -36,5 +36,4 @@ commands =
 # E123, E125 skipped as they are invalid PEP-8.
 show-source = True
 ignore = E123,E125
-builtins = _
 exclude=.venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,build