def _mails(self, users_and_watches):
        # Did this instead of mail() because a common case might be sending the
        # same mail to many users. mail() would make it difficult to avoid
        # redoing the templating every time.
        raise NotImplementedError
Return an iterable yielding an EmailMessage to send to each user.
dataset/ETHPy150Open mozilla/django-tidings/tidings/events.py/Event._mails