diff --git a/jupyter_server/gateway/managers.py b/jupyter_server/gateway/managers.py
index 423148fa81..e1fb16908b 100644
--- a/jupyter_server/gateway/managers.py
+++ b/jupyter_server/gateway/managers.py
@@ -17,12 +17,12 @@
 from jupyter_client.manager import AsyncKernelManager
 from jupyter_client.managerabc import KernelManagerABC
 from jupyter_server_kernels.kernels.kernelmanager import AsyncMappingKernelManager
+from jupyter_server_kernels.sessions.sessionmanager import SessionManager
 from tornado import web
 from tornado.escape import json_decode, json_encode, url_escape, utf8
 from traitlets import DottedObjectName, Instance, Type, default
 
 from .._tz import UTC
-from jupyter_server_kernels.sessions.sessionmanager import SessionManager
 from ..utils import ensure_async, url_path_join
 from .gateway_client import GatewayClient, gateway_request
 
diff --git a/tests/services/kernels/test_config.py b/tests/services/kernels/test_config.py
index ba31f16998..983abc12d4 100644
--- a/tests/services/kernels/test_config.py
+++ b/tests/services/kernels/test_config.py
@@ -1,7 +1,6 @@
 import pytest
-from traitlets.config import Config
-
 from jupyter_server_kernels.kernels.kernelmanager import AsyncMappingKernelManager
+from traitlets.config import Config
 
 
 @pytest.fixture
diff --git a/tests/services/kernels/test_connection.py b/tests/services/kernels/test_connection.py
index d6eed57dc3..d3ec54459b 100644
--- a/tests/services/kernels/test_connection.py
+++ b/tests/services/kernels/test_connection.py
@@ -4,13 +4,13 @@
 
 from jupyter_client.jsonutil import json_clean, json_default
 from jupyter_client.session import Session
+from jupyter_server_kernels.kernels.connection.channels import (
+    ZMQChannelsWebsocketConnection,
+)
 from tornado.httpserver import HTTPRequest
 from tornado.websocket import WebSocketHandler
 
 from jupyter_server.serverapp import ServerApp
-from jupyter_server_kernels.kernels.connection.channels import (
-    ZMQChannelsWebsocketConnection,
-)
 
 
 async def test_websocket_connection(jp_serverapp):
diff --git a/tests/services/sessions/test_api.py b/tests/services/sessions/test_api.py
index 4f9fa8c8e6..2ac6eb1a7f 100644
--- a/tests/services/sessions/test_api.py
+++ b/tests/services/sessions/test_api.py
@@ -10,12 +10,12 @@
 import pytest
 import tornado
 from jupyter_client.ioloop import AsyncIOLoopKernelManager
+from jupyter_server_kernels.kernels.kernelmanager import AsyncMappingKernelManager
 from nbformat import writes
 from nbformat.v4 import new_notebook
 from tornado.httpclient import HTTPClientError
 from traitlets import default
 
-from jupyter_server_kernels.kernels.kernelmanager import AsyncMappingKernelManager
 from jupyter_server.utils import url_path_join
 
 from ...utils import expected_http_error
diff --git a/tests/services/sessions/test_manager.py b/tests/services/sessions/test_manager.py
index ffc398dc56..c7746f4f52 100644
--- a/tests/services/sessions/test_manager.py
+++ b/tests/services/sessions/test_manager.py
@@ -1,11 +1,6 @@
 import asyncio
 
 import pytest
-from tornado import web
-from traitlets import TraitError
-
-from jupyter_server._tz import isoformat, utcnow
-from jupyter_server.services.contents.manager import ContentsManager
 from jupyter_server_kernels.kernels.kernelmanager import MappingKernelManager
 from jupyter_server_kernels.sessions.sessionmanager import (
     KernelSessionRecord,
@@ -13,6 +8,11 @@
     KernelSessionRecordList,
     SessionManager,
 )
+from tornado import web
+from traitlets import TraitError
+
+from jupyter_server._tz import isoformat, utcnow
+from jupyter_server.services.contents.manager import ContentsManager
 
 
 class DummyKernel:
diff --git a/tests/test_serialize.py b/tests/test_serialize.py
index a8c3a6e6b5..bc4f79ad05 100644
--- a/tests/test_serialize.py
+++ b/tests/test_serialize.py
@@ -2,7 +2,6 @@
 import os
 
 from jupyter_client.session import Session
-
 from jupyter_server_kernels.kernels.connection.base import (
     deserialize_binary_message,
     serialize_binary_message,