add cancel schedule

orders-events/tests/events/billing/test_cancel_enrollment.py

@@ -30,14 +30,14 @@ def test_cancel_enrollment(
     lambda_context: LambdaContext,
 ):
     now_ = now()
-    start_date, end_date = get_billing_period(
+    start_period, end_period = get_billing_period(
         billing_day=6,
         date_=now_,
     )
     pk = 'BILLING#ORG#cJtK9SsnJhKPyxESe7g3DG'
     sk = 'START#{start}#END#{end}#ENROLLMENT#{enrollment_id}'.format(
-        start=start_date.isoformat(),
-        end=end_date.isoformat(),
+        start=start_period.isoformat(),
+        end=end_period.isoformat(),
         enrollment_id=enrollment_id,
     )
     # Add up-to-date enrollment item to billing