def top_referrers(self, domain_only=True):
referrer = self._referrer_clause(domain_only)<EOL>return (self.get_query()<EOL>.select(referrer, fn.Count(PageView.id))<EOL>.group_by(referrer)<EOL>.order_by(fn.Count(PageView.id).desc())<EOL>.tuples())<EOL>
What domains send us the most traffic?