If you define an invoice method on a class, you have no way of knowing that some other user of that class won't define a different, incompatible method also named invoice.

Unfortunately, it is incompatible because at the metadata level every method on every interface has its own slot (which makes explicit interface implementations work).

Results show that the method of radiation enhancing interphase reaction is an effective path for improving incompatible polymers' interphase adhesion.