Controller modification in hooks


I’m pretty sure there’s an answer out there, I’ve tried googling, reading through the docs… but am unable to figure out why hooks don’t seem to override.

I’ve been trying to hook certain methods that are found in etc. These are not defined doctypes, but they are Parents. For instance PurchaseInvoice imports BuyingController.

I want to create a new method under BuyingController. Would it be sufficient to extend the the child’s method?