add cancel schedule

orders-events/app/events/billing/append_enrollment.py

@@ -62,14 +62,14 @@ def lambda_handler(event: EventBridgeEvent, context: LambdaContext) -> bool:
         enrollment['course'] = old_course
 
     created_at: datetime = fromisoformat(enrollment['created_at'])  # type: ignore
-    start_date, end_date = get_billing_period(
+    start_period, end_period = get_billing_period(
         billing_day=new_image['billing_day'],
         date_=created_at,
     )
     pk = 'BILLING#ORG#{org_id}'.format(org_id=org_id)
     sk = 'START#{start}#END#{end}'.format(
-        start=start_date.isoformat(),
-        end=end_date.isoformat(),
+        start=start_period.isoformat(),
+        end=end_period.isoformat(),
     )
 
     logger.info('Enrollment found', data=enrollment)
@@ -91,7 +91,8 @@ def lambda_handler(event: EventBridgeEvent, context: LambdaContext) -> bool:
                     'id': pk,
                     'sk': f'{sk}#SCHEDULE#AUTO_CLOSE',
                     'ttl': ttl(
-                        start_dt=datetime.combine(end_date, time()) + timedelta(days=1)
+                        start_dt=datetime.combine(end_period, time())
+                        + timedelta(days=1)
                     ),
                     'created_at': now_,
                 }