I am learning the Checkout SDK and am seeing articles such as this:
https://developer.paypal.com/docs/checkout/integration-features/handle-errors/
What seems to be missing is a general reference guide on the details of such calls. For instance, what is `err` in the provided method found in the above article? In particular, what are its available properties and methods?
Additionally, I am looking for a comprehensive list of all the methods in addition to `onError`.
It would be super useful if someone could point me to a detailed reference guide for this SDK. Thank you for any assistance!
