protected function _createSortFieldOption($field, $dir, $options)
    {
        $sortField = $this->sortFields[$field];
        if (isset($sortField['custom'])) {
            if (!is_array($sortField['custom'])) {
                $sortField['custom'] = [$sortField['custom']];
            }
            foreach ($sortField['custom'] as $sortEntry) {
                $options['order'][] = preg_replace('/:dir/', $dir, $sortEntry);
            }
        } else {
            $options['order'][] = $sortField['modelField'] . ' ' . $dir;
        }

        return $options;
    }