SITE_URLS = [webapp2.Route('/', handler=HomePageHandler, name='route-home'),
    webapp2.Route('/feed/<:(create/?)|edit/><entity_id:(\\d*)>', handler=
    MyFeedHandler, name='route-entity-create-or-edit'), webapp2.SimpleRoute
    ('/feed/?', handler=MyFeedListHandler, name='route-entity-list')]
How do I make a trailing slash optional with webapp2?