public function first()
    {
        $item = reset($this->items);
        if (is_numeric($item)) {
            $item = DataObject::get_by_id($this->dataClass, $item);
        }
        if (!empty($this->extraFields[key($this->items)])) {
            $item->update($this->extraFields[key($this->items)]);
        }
        return $item;
    }