def METHOD_NAME(self, slug):
    if slug not in self.jur_cache:
        try:
            jur = Jurisdiction.objects.get(slug=slug)
        except Jurisdiction.DoesNotExist:
            raise ValueError(_('Jurisdiction slug "%s" does not exist.') % slug)
        jur.laws = jur.get_all_laws()
        self.jur_cache[slug] = jur
    return self.jur_cache[slug]