Redirecting preview function based on draft_id

def preview_article(self, request, object_id, language):
        """Redirecting preview function based on draft_id
        """
        article = get_object_or_404(self.model, id=object_id)
        attrs = '?%s' % get_cms_setting('CMS_TOOLBAR_URL__EDIT_ON')
        attrs += '&language=' + language
        with force_language(language):
            url = article.get_absolute_url(language) + attrs
        return HttpResponseRedirect(url)