public function sortAdminColumns($vars)
    {
        if (!isset($vars['orderby'])) {
            return $vars;
        }

        $admin_columns = $this->getAdminColumns();
        if (!Arr::iterable($admin_columns)) {
            return $vars;
        }

        foreach ($admin_columns as $k) {
            if ($vars['orderby'] !== $k) {
                continue;
            }

            $vars = array_merge($vars, array(
                'meta_key'=> $k,
                'orderby' => 'meta_value'
            ));

            break;
        }
        return $vars;
    }