Returns count of new topics since last visit, or one day.
    {% get_new_topics_count as new_topic_count %}

def get_new_topics_count(last_seen=None, for_member=False):
    """
    Returns count of new topics since last visit, or one day.
    {% get_new_topics_count as new_topic_count %}
    """
    if not last_seen:
        last_seen = yesterday()
    if not for_member:
        return Topic.objects.filter(created__gt=last_seen).count()
    return Topic.objects.filter(modified__gt=last_seen, user__id=for_member).count()