def do_filter_ranking(self, engine_slug, queryset, search_text):
        return queryset.extra(
            select = {
                "watson_rank": "1",
            },
        )
If `rex` expression is not found then raise `DataNotFound` exception.
dataset/ETHPy150Open etianen/django-watson/src/watson/backends.py/SearchBackend.do_filter_ranking--crossover with--dataset/ETHPy150Open lorien/grab/grab/document.py/RegexpExtension.rex_assert