diff --git a/goodtimes/webhook/payment_processing_service.py b/goodtimes/webhook/payment_processing_service.py
index e333f43..95ff625 100644
--- a/goodtimes/webhook/payment_processing_service.py
+++ b/goodtimes/webhook/payment_processing_service.py
@@ -63,17 +63,17 @@ class PaymentProcessingService:
         )
         return transaction
 
-    def process_event(self, transactio):
+    def process_event(self):
         event_type = self.webhook_service.event_type
         if event_type == "checkout.session.completed":
-            self.handle_success(transactio)
+            self.handle_success()
         elif event_type == "invoice.payment_succeeded":
             if self.charge_data.get("billing_reason") != "subscription_create":
-                self.handle_success(transactio)
+                self.handle_success()
         else:
-            self.handle_failure(transactio)
+            self.handle_failure()
 
-    def handle_success(self, transactio):
+    def handle_success(self):
         with transaction.atomic():
             # Create or update the principal subscription
             transactio = self.create_transaction()