diff --git a/jupyter_server/serverapp.py b/jupyter_server/serverapp.py
index b0c5e5e1fa..1bb02358a1 100644
--- a/jupyter_server/serverapp.py
+++ b/jupyter_server/serverapp.py
@@ -1740,7 +1740,9 @@ def _root_dir_changed(self, change: t.Any) -> None:
 
     preferred_dir = Unicode(
         config=True,
-        help=trans.gettext("Preferred starting directory to use for notebooks and kernels. ServerApp.preferred_dir is deprecated in jupyter-server 2.0. Use FileContentsManager.preferred_dir instead"),
+        help=trans.gettext(
+            "Preferred starting directory to use for notebooks and kernels. ServerApp.preferred_dir is deprecated in jupyter-server 2.0. Use FileContentsManager.preferred_dir instead"
+        ),
     )
 
     @default("preferred_dir")