diff --git a/oauthenticator/generic.py b/oauthenticator/generic.py
index 20282ee9..93ef695a 100644
--- a/oauthenticator/generic.py
+++ b/oauthenticator/generic.py
@@ -3,12 +3,11 @@
 """
 
 import os
-from functools import reduce
 
 from jupyterhub.auth import LocalAuthenticator
 from jupyterhub.traitlets import Callable
 from tornado.httpclient import AsyncHTTPClient
-from traitlets import Bool, Dict, Set, Unicode, Union, default
+from traitlets import Bool, Dict, Unicode, Union, default
 
 from .oauth2 import OAuthenticator
 
@@ -18,7 +17,6 @@ class GenericOAuthenticator(OAuthenticator):
     def _login_service_default(self):
         return os.environ.get("LOGIN_SERVICE", "OAuth 2.0")
 
-
     @default("http_client")
     def _default_http_client(self):
         return AsyncHTTPClient(
@@ -59,6 +57,5 @@ def _default_http_client(self):
     )
 
 
-
 class LocalGenericOAuthenticator(LocalAuthenticator, GenericOAuthenticator):
     """A version that mixes in local system user creation"""
diff --git a/oauthenticator/oauth2.py b/oauthenticator/oauth2.py
index 5a6f1d46..33ad10a6 100644
--- a/oauthenticator/oauth2.py
+++ b/oauthenticator/oauth2.py
@@ -7,8 +7,8 @@
 import base64
 import json
 import os
-from functools import reduce
 import uuid
+from functools import reduce
 from urllib.parse import quote, urlencode, urlparse, urlunparse
 
 import jwt
@@ -21,7 +21,18 @@
 from tornado.httpclient import AsyncHTTPClient, HTTPClientError, HTTPRequest
 from tornado.httputil import url_concat
 from tornado.log import app_log
-from traitlets import Any, Bool, Callable, Dict, List, Unicode, Union, Set, default, validate
+from traitlets import (
+    Any,
+    Bool,
+    Callable,
+    Dict,
+    List,
+    Set,
+    Unicode,
+    Union,
+    default,
+    validate,
+)
 
 
 def guess_callback_uri(protocol, host, hub_server_url):