Features: 1) Add additional filters to promocodes query, including used_on__isnull and start_time__lte.

Fixes: None;

Extra: 1) Adjust query formatting for improved readability.

core/graphene/schema.py

@@ -290,7 +290,12 @@ class Query(ObjectType):
         promocodes = PromoCode.objects
         if info.context.user.has_perm("core.view_promocode"):
             return promocodes.filter(user__uuid=kwargs.get("user_uuid")) or promocodes.all()
-        return promocodes.filter(is_active=True, user=info.context.user)
+        return promocodes.filter(
+            is_active=True,
+            user=info.context.user,
+            used_on__isnull=True,
+            start_time__lte=info.context.now,
+            )
 
     @staticmethod
     def resolve_product_tags(_parent, info, **_kwargs):