diff --git a/helpers/models.py b/helpers/models.py
index 9ad46c0..4bb86a0 100644
--- a/helpers/models.py
+++ b/helpers/models.py
@@ -31,8 +31,7 @@ USchema = marshmallow_dataclass.class_schema(User)
 
 class UserSchema(USchema):
 
-    @pre_load
-    def stringify_time(self, data, many, **kwargs):
-        if 'next_daily_notify_time' in data:
-            data['next_daily_notify_time'] = str(data['next_daily_notify_time'])
-        return data
+    def load(self, entity, *args, **kwargs):
+        if 'next_daily_notify_time' in entity:
+            entity['next_daily_notify_time'] = str(entity['next_daily_notify_time'])
+        return super().load(entity, *args, **kwargs)