def query(self, querystring):
        """
        creates :class:`notmuch.Query` objects on demand

        :param querystring: The query string to use for the lookup
        :type query: str.
        :returns: :class:`notmuch.Query` -- the query object.
        """
        mode = Database.MODE.READ_ONLY
        db = Database(path=self.path, mode=mode)
        q = db.create_query(querystring)
        # add configured exclude tags
        for tag in settings.get('exclude_tags'):
            q.exclude_tag(tag)
        return q
creates :class:`notmuch.Query` objects on demand

        :param querystring: The query string to use for the lookup
        :type query: str.
        :returns: :class:`notmuch.Query` -- the query object.