diff --git a/tox.ini b/tox.ini
index 9e892c4..2d6f50a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,5 +11,5 @@ python_files = linux_utils/tests.py
 
 [flake8]
 exclude = .tox
-ignore-extend = D211,D400,D401
+extend-ignore = D211,D400,D401
 max-line-length = 120