how to call job function on customized day?

Hi,
in python back-end, if we have a use subscription expiry date. And i want to notify the user and also send a email to user before 5 days of expiry and 2 days and 1 days... How to approach to that?
Has any one worked on a project like that?

No files, tests, or entry points are identified in the issue. Start by reviewing the scheduler's documented date and job APIs, then determine whether reminders relative to a subscription expiry date are supported; done would require an agreed approach for the three reminder times and its expected scheduling behavior.

Written by the indexing model from the issue text.