diff --git a/tox.ini b/tox.ini
index cf8e1753..383a050b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -50,7 +50,7 @@ commands = sphinx-build -W -b html doc/source doc/build/html
 
 [flake8]
 show-source = True
-enable-extensions = H203,H106
+enable-extensions = H106,H203,H904
 exclude=.venv,.git,.tox,dist,*lib/python*,*egg,build
 max-complexity=20