What happens?:

As shown in the doc Site.notifications() does not yield Notification objects. Instead it returns a tuple of all collected Notifications

What should have happened instead?:
Notification objects should be yielded. Also continueing of the request should be handled. Due to backward compatibility this should become a new method. The old one should be deprecated then.

Software version:
Pywikibot 3+ (2.0?), contributed with rPWBCe3de553