Unabled to create Subscriptions with schedule as "On Extract Refresh" #1658

Subscriptions can be created on specific schedules. However, it is not possible to create subscriptions based on extract refresh. The SubscriptionItem class (subject, schedule_id, user_id, target) requires schedule_id as a mandatory parameter, so it cannot be ignored or set to None.

I have read some articles to ignore/ dont pass "schedule_id" but it doesn't seems to be working.

Env:

• Tableau Server: On Prem: 2025.1.1 (20251.25.0415.1018) 64-bit Windows
• Python version: 3.12.0
• TSC library version: 0.38.

To Reproduce
Try to create a subcription that should have schedule as "On Extract Refresh"

Results
Error When None is passed to Scheduled ID: new_sub = TSC.SubscriptionItem(email_subject, schedule_id=None, user_id, target)
INFO Creating a subscription (<Subscription subject(Test_User_TestSubscriptions2_withoutschedule) schedule_id(None) user_id(f57ca8cb-4a14-4b01-ac7b-721ffe260537) target(<Target#761209c1-decd-4626-8bbb-7be632e2efe8, view>))
Failed to create subscription. below is the error message
INFO cannot serialize None (type NoneType)

Error When Schedule_Id parameter is skipped: new_sub = TSC.SubscriptionItem(email_subject, user_id, target)
SubscriptionItem.init() missing 1 required positional argument: 'schedule_id'

please suggest if I'm missing any