scrapy yield Request

import scrapy
from myproject.items import MyItem
class MySpider(scrapy.Spider):
name = ’example.com’ allowed_domains = [’example.com’] start_urls = [
        ’http://www.example.com/1.html’,
        ’http://www.example.com/2.html’,
        ’http://www.example.com/3.html’,
]
def parse(self, response):
　　for h3 in response.xpath(’//h3’).extract():
　　　　yield MyItem(title=h3)
　　for url in response.xpath(’//a/@href’).extract(): 
　　　　yield scrapy.Request(url, callback=self.parse)