diff --git a/notebook/__main__.py b/notebook/__main__.py
index c05250a257..403106406c 100644
--- a/notebook/__main__.py
+++ b/notebook/__main__.py
@@ -1,4 +1,5 @@
 """CLI entry point for notebook."""
+
 import sys
 
 from notebook.app import main
diff --git a/notebook/_version.py b/notebook/_version.py
index 55e5766f7f..864b08edbe 100644
--- a/notebook/_version.py
+++ b/notebook/_version.py
@@ -1,4 +1,5 @@
 """Version info for notebook."""
+
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 import re
diff --git a/notebook/app.py b/notebook/app.py
index 9a969b50a7..bfd0dce2b9 100644
--- a/notebook/app.py
+++ b/notebook/app.py
@@ -1,4 +1,5 @@
 """Jupyter notebook application."""
+
 from __future__ import annotations
 
 import os