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

def get_queryset(self):
        try:
            cal_slug = self.kwargs['cal_slug']
            self.calendar = get_object_or_404(Calendar, slug=cal_slug)
        except:
            self.calendar = None
        return EventTime.upcoming_objects.all()

"""Calendar model."""

    class Meta:
        verbose_name = _('calendar')
        verbose_name_plural=_('calendars')

    def __unicode__(self):
        return self.title

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

class Event(TitleSlugDescriptionModel, TimeStampedModel):
    """Event model"""
    calendar=models.ForeignKey(Calendar, blank=True, null=True)
    submitted_by = models.ForeignKey(User, blank=True, null=True)

    class Meta:
        verbose_name = _('event')
        verbose_name_plural = _('events')

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

    @property
    def upcoming_event_times(self):
        if not self._upcoming:
            try:
                times = self.event_times.all().filter(start__gte=datetime.now().date)

from django.conf.urls.defaults import *
from django.views.generic import ListView, DetailView
from eventy.models import Event, EventTime, Calendar, Place
from eventy.views import EventDetailView, EventDayView, EventMonthView, EventYearView, EventListView

urlpatterns = patterns('',
    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'),
)