def get_urls(self):
        """
        Generate the list of URL patterns including the registered single
        object routers urls.
        """
        base_urls = super(SimpleRouter, self).get_urls()
        single_urls = sum([r.urls for r in self._single_object_registry], [])
        nested_urls = sum([r.urls for r in self._nested_object_registry], [])

        return base_urls + single_urls + nested_urls
Generate the list of URL patterns including the registered single
        object routers urls.