I want to override the core class method in my custom file

Frappe Framework
1

how to override the core class method in my custom file

2

https://frappeframework.com/docs/user/en/python-api/hooks#override-doctype-class

3

Or look at monkey patch if method are not while listed (it’s not documented in frappe cause it’s more a python feature, you can find example here GitHub - aakvatech/CSF_TZ)