How to use the eventy.models.Event function in eventy

self._past= times
        return self._past

    def __unicode__(self):
        return self.title

    @models.permalink
    def get_absolute_url(self):
        return ('event-info', None, { 'slug': self.event.slug, })


class EventTime(models.Model):
    """EventTime model
    
    This model does most of the heavy lifting as to whether """
    event = models.ForeignKey(Event, related_name='event_times')
    start = models.DateTimeField()
    end = models.DateTimeField(blank=True, null=True)
    place = models.ForeignKey(Place, blank=True, null=True)
    place_string = models.CharField(_('One-off place'), max_length=200, blank=True)
    is_all_day = models.BooleanField(default=False)
    notes = models.TextField(_('Notes'), blank=True, null=True)
    slug = models.SlugField(_('Event slug'), blank=True, editable=False)

    objects = models.Manager()
    upcoming_objects = UpcomingManager()

    class Meta:
        verbose_name = _('event time')
        verbose_name_plural = _('event times')
        get_latest_by = 'start'

url(r'^(?P\d{4})/(?P\w{3})/(?P\d{1,2})/$', view=EventDayView.as_view(),    name='ev-events-day'),
    url(r'^(?P\d{4})/(?P\w{3})/$',                  view=EventMonthView.as_view(),  name='ev-events-month'),
    url(r'^(?P\d{4})/$',                                   view=EventYearView.as_view(),   name='ev-events-year'),

    url(r'^calendars/(?P[-\w]+)/(?P\d{4})/$',                  view=EventYearView.as_view(),   name='ev-calendar-year'),
    url(r'^calendars/(?P[-\w]+)/(?P\d{4})/(?P\w{3})/$', view=EventMonthView.as_view(),  name='ev-calendar-month'),
    url(r'^calendars/(?P[-\w]+)/$',                                  view=EventListView.as_view(),   name='ev-calendar-detail'),
    url(r'^calendars/$',                                                       view=ListView.as_view(model=Calendar), name='ev-calendar-list'),

    url(r'^places/$', view=ListView.as_view(model=Place), name='place-list'),
    url(r'^places/(?P[-\w]+)/$', view=DetailView.as_view(model=Place), name='place-detail'),

    url(r'^(?P[-\w]+)/(?P\d{4})/(?P\w{3})/(?P\d{1,2})/$', view=EventDetailView.as_view(), name='ev-event-detail'),
    url(r'^(?P[-\w]+)/(?P\d{4})/(?P\w{3})/$',                  view=EventMonthView.as_view(),  name='ev-event-month'),
    url(r'^(?P[-\w]+)/(?P\d{4})/$',                                   view=EventYearView.as_view(),   name='ev-event-year'),
    url(r'^(?P[-\w]+)/$',                                                   view=DetailView.as_view(model=Event), name='ev-events-info'),
    url(r'^$', view=EventListView.as_view(), name='event-list'),
)

def past_event_times(self):
        if not self._past:
            try:
                times = self.event_times.all().filter(start__lte=datetime.now().date)
            except(Event.DoesNotExist, IndexError):
                times = None
            self._past= times
        return self._past

def __init__(self, *args, **kwargs):
        super (Event, self).__init__(*args, **kwargs)
        self._upcoming = None
        self._past = None