diff --git a/tox.ini b/tox.ini
index cd6d4e43..51d39f80 100644
--- a/tox.ini
+++ b/tox.ini
@@ -60,8 +60,11 @@ commands =
     oslo-config-generator --config-file=etc/castellan/sample-config-generator.conf
 
 [flake8]
+# [H106] Don't put vim configuration in source files.
+# [H203] Use assertIs(Not)None to check for None.
 show-source = True
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
+enable-extensions = H106,H203
 
 [hacking]
 import_exceptions = castellan.i18n