diff --git a/AUTHORS b/AUTHORS
index 57065c5..db11c06 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -1,4 +1,5 @@
 Chris Sibbitt <csibbitt@redhat.com>
+Erno Kuvaja <jokke@usr.fi>
 Jaromír Wysoglad <jwysogla@redhat.com>
 Leif Madsen <leif@leifmadsen.com>
 Leif Madsen <lmadsen@redhat.com>
diff --git a/observabilityclient/prometheus_client.py b/observabilityclient/prometheus_client.py
index 1e0ad95..88a3b2b 100644
--- a/observabilityclient/prometheus_client.py
+++ b/observabilityclient/prometheus_client.py
@@ -47,14 +47,14 @@ class PrometheusAPIClientError(Exception):
             return f'[{decoded.status}]'
 
 
-class PrometheusMetric:
+class PrometheusMetric(object):
     def __init__(self, input):
         self.timestamp = input['value'][0]
         self.labels = input['metric']
         self.value = input['value'][1]
 
 
-class PrometheusAPIClient:
+class PrometheusAPIClient(object):
     def __init__(self, host):
         self._host = host
         self._session = requests.Session()
diff --git a/observabilityclient/tests/unit/test_rbac.py b/observabilityclient/tests/unit/test_rbac.py
index fee81f7..d371347 100644
--- a/observabilityclient/tests/unit/test_rbac.py
+++ b/observabilityclient/tests/unit/test_rbac.py
@@ -16,7 +16,6 @@ from unittest import mock
 
 from keystoneauth1.exceptions.auth_plugins import MissingAuthPlugin
 from keystoneauth1 import session
-
 import testtools
 
 from observabilityclient.v1 import rbac
@@ -44,7 +43,7 @@ class RbacTest(testtools.TestCase):
         with mock.patch.object(session.Session, 'get_project_id',
                                side_effect=MissingAuthPlugin()):
             r = rbac.Rbac("client", session.Session(), False)
-            self.assertEqual(r.project_id, None)
+            self.assertIsNone(r.project_id)
 
     def test_enrich_query(self):
         test_cases = [
diff --git a/observabilityclient/tests/unit/test_utils.py b/observabilityclient/tests/unit/test_utils.py
index 3386033..871b856 100644
--- a/observabilityclient/tests/unit/test_utils.py
+++ b/observabilityclient/tests/unit/test_utils.py
@@ -40,7 +40,7 @@ class GetConfigFileTest(testtools.TestCase):
         with mock.patch.object(os.path, 'exists', return_value=False) as m:
             ret = metric_utils.get_config_file()
         m.call_args_list == expected
-        self.assertEqual(ret, None)
+        self.assertIsNone(ret)
 
 
 class GetPrometheusClientTest(testtools.TestCase):
diff --git a/observabilityclient/v1/rbac.py b/observabilityclient/v1/rbac.py
index 96c74e6..f682110 100644
--- a/observabilityclient/v1/rbac.py
+++ b/observabilityclient/v1/rbac.py
@@ -23,7 +23,7 @@ class ObservabilityRbacError(Exception):
     pass
 
 
-class Rbac():
+class Rbac(object):
     def __init__(self, client, session, disable_rbac=False):
         self.client = client
         self.session = session
diff --git a/tox.ini b/tox.ini
index 2587f20..b0c753a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -37,9 +37,34 @@ commands = observabilityclient {posargs:observabilityclient/tests}
 
 [flake8]
 show-source = True
-ignore = D100,D101,D102,D103,D104,D105,D106,D107,A002,A003,W504,W503
-exclude=.git,.tox,dist,doc,*egg,build
-enable-extensions=G
+# A002 argument "input" is shadowing a python builtin
+# A003 class attribute "list" is shadowing a python builtin
+# D100 Missing docstring in public module
+# D101 Missing docstring in public class
+# D102 Missing docstring in public method
+# D103 Missing docstring in public function
+# D104 Missing docstring in public package
+# D105 Missing docstring in magic method
+# D106 Missing docstring in public nested class
+# D107 Missing docstring in __init__
+# W503 line break before binary operator
+# W504 line break after binary operator
+ignore = A002,A003,D100,D101,D102,D103,D104,D105,D106,D107,W503,W504
+exclude=.venv,.git,.tox,dist,doc,*egg,build
+# [H101] Include your name with TODOs as in # TODO(yourname).
+# [H104] Empty files should not contain license or comments
+# [H106] Do not put vim configuration in source files.
+# [H201] Do not write except:, use except Exception: at the very least.
+# [H202] Testing for Exception being raised
+# [H203] Use assertIs(Not)None to check for None.
+# [H204] Use assert(Not)Equal to check for equality.
+# [H205] Use assert(Greater|Less)(Equal) for comparison.
+# [H23] Py3 compat
+# [H301] Do not import more than one module per line (*)
+# [H303] Do not use wildcard * import (*)
+# [H304] Do not make relative imports
+# [H306] Alphabetically order your imports by the full module path.
+enable-extensions=G,H101,H104,H106,H201,H202,H203,H204,H205,H23,H301,H303,H304,H306
 application-import-names = observabilityclient
 
 [pytest]