[pre-commit.ci] auto fixes from pre-commit.com hooks

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examples/service-whoami-flask/whoami-flask.py

@@ -9,6 +9,7 @@ import secrets
 from functools import wraps
 
 from flask import Flask, Response, make_response, redirect, request, session
+
 from jupyterhub.services.auth import HubOAuth
 
 prefix = os.environ.get('JUPYTERHUB_SERVICE_PREFIX', '/')