diff --git a/tox.ini b/tox.ini
index be35509..d2e83e9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -53,9 +53,9 @@
 commands = oslo_debug_helper -t patrole_tempest_plugin/tests {posargs}
 
 [flake8]
-# E123, E125 skipped as they are invalid PEP-8.
-
+enable-extensions = H106,H203,H904
 show-source = True
+# E123, E125 skipped as they are invalid PEP-8.
 ignore = E123,E125
 builtins = _
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build