Check if there is a live chat that ended in the last 3 days, and
            return it. We will display a link to it on the articles page.

def get_last_live_chat(self):
        """ Check if there is a live chat that ended in the last 3 days, and
            return it. We will display a link to it on the articles page.
        """
        now = datetime.now()

        lcqs = self.get_query_set()
        lcqs = lcqs.filter(
            chat_ends_at__lte=now,
            ).order_by('-chat_ends_at')
        for itm in lcqs:
            if itm.chat_ends_at + timedelta(days=3) > now:
                return itm
        return None