diff --git a/backend/categorisation/processor.py b/backend/categorisation/processor.py
index 68e8c991..7c5698b7 100644
--- a/backend/categorisation/processor.py
+++ b/backend/categorisation/processor.py
@@ -72,7 +72,7 @@ def _choose_cheapest_relevant_plan(plans: List[Plan]) -> Plan:
     return cheapest_plan
 
 
-def _update_default_flags(plans: List["Plan"], cheapest_plan: Plan) -> None:
+def _update_default_flags(plans: List[Plan], cheapest_plan: Plan) -> None:
     plans_to_update: List[Plan] = []
 
     for plan in plans: