diff --git a/datagateway_api/common/database/helpers.py b/datagateway_api/common/database/helpers.py
index c57d38ff..bf19a65d 100644
--- a/datagateway_api/common/database/helpers.py
+++ b/datagateway_api/common/database/helpers.py
@@ -3,8 +3,8 @@
 from functools import wraps
 import logging
 
-from sqlalchemy.orm import aliased
 from flask_sqlalchemy import SQLAlchemy
+from sqlalchemy.orm import aliased
 
 from datagateway_api.common.database.filters import (
     DatabaseIncludeFilter as IncludeFilter,
@@ -30,6 +30,7 @@
 
 db = SQLAlchemy()
 
+
 def requires_session_id(method):
     """
     Decorator for database backend methods that makes sure a valid session_id is
@@ -89,7 +90,7 @@ def commit_changes(self):
         try:
             self.session.commit()
         except Exception as e:
-            log.error(f"Error whilst committing changes to {self.table}, rolling back")
+            log.error("Error whilst committing changes to %s, rolling back", self.table)
             self.session.rollback()
             raise e