The problem: how is get_shipping_address_for_paypal() implemented?

I think there would be a cleaner solution if you provide a provider method. In best case we could merge our efforts:
#149

This pull request is missing the code for get_shipping_address_for_paypal() and appears to be abandoned. I'd suggest closing.

In case interest in this re-arises, the shipping address should ideally be a dataclass, to make it obvious how it should be implemented and facilitate type checking.