假设我有一个Bookitem，我需要在解析阶段和详细信息阶段都向其中添加信息

def parse(self, response)
    data = json.loads(response)
    for book in data['result']:
        item = BookItem();
        item['id'] = book['id']
        url = book['url']
        yield Request(url, callback=self.detail)

def detail(self,response):        
    hxs = HtmlXPathSelector(response)
    item['price'] = ......
#I want to continue the same book item as from the for loop above

按原样使用代码将导致详细阶段中未定义的项目。如何将物品传递到细节？细节（自我，响应，项目）似乎不起作用。