diff --git a/ansible/library/kolla_docker.py b/ansible/library/kolla_docker.py
index 7b150f078e..8c7cab7aee 100644
--- a/ansible/library/kolla_docker.py
+++ b/ansible/library/kolla_docker.py
@@ -624,8 +624,8 @@ class DockerWorker(object):
 
             split_vol = vol.split(':')
 
-            if (len(split_vol) == 2
-               and ('/' not in split_vol[0] or '/' in split_vol[1])):
+            if (len(split_vol) == 2 and
+               ('/' not in split_vol[0] or '/' in split_vol[1])):
                 split_vol.append('rw')
 
             vol_list.append(split_vol[1])
diff --git a/kolla_ansible/cmd/genpwd.py b/kolla_ansible/cmd/genpwd.py
index 60e508397b..17c37efb36 100755
--- a/kolla_ansible/cmd/genpwd.py
+++ b/kolla_ansible/cmd/genpwd.py
@@ -61,9 +61,9 @@ def genpwd(passwords_file, length, uuid_keys, ssh_keys, blank_keys,
 
     for k, v in passwords.items():
         if (k in ssh_keys and
-                (v is None
-                 or v.get('public_key') is None
-                 and v.get('private_key') is None)):
+                (v is None or
+                 v.get('public_key') is None and
+                 v.get('private_key') is None)):
             private_key, public_key = generate_RSA()
             passwords[k] = {
                 'private_key': private_key,
diff --git a/tox.ini b/tox.ini
index 9f1b6c296a..38a521b4ea 100644
--- a/tox.ini
+++ b/tox.ini
@@ -98,10 +98,10 @@ commands =
 [flake8]
 show-source = True
 # NOTE: Default ignore list is *not* empty!
-# TODO: Enable either W503 or W504:
-# W503 line break before binary operator
 # W504 line break after binary operator
-ignore = W503,W504
+# (W503 and W504 are incompatible and we need to choose one of them.
+#  Existing codes follows W503, so we disable W504.):
+ignore = W504
 exclude=.eggs,.git,.tox,doc
 
 [testenv:lower-constraints]