diff --git a/egi_notebooks_hub/egiauthenticator.py b/egi_notebooks_hub/egiauthenticator.py
index 829635b..f6c3e83 100644
--- a/egi_notebooks_hub/egiauthenticator.py
+++ b/egi_notebooks_hub/egiauthenticator.py
@@ -21,6 +21,7 @@
 
 class JWTHandler(BaseHandler):
     """Handler for authentication with JWT tokens"""
+
     async def exchange_for_refresh_token(self, access_token):
         self.log.debug("Exchanging access token for refresh")
         http_client = AsyncHTTPClient()