Return multiple rows.

def _fetchall(self, query, vars, limit=None, offset=0):
        """
        Return multiple rows.
        """
        if limit is None:
            limit = current_app.config['DEFAULT_PAGE_SIZE']
        query += ' LIMIT %s OFFSET %s''' % (limit, offset)
        cursor = self.get_db().cursor()
        self._log(cursor, query, vars)
        cursor.execute(query, vars)
        return cursor.fetchall()