python xpath图片爬取

import requests
from urllib.request import urlretrieve
from lxml import etree

headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36'
}

url = 'http://www.win4000.com/zt/qsmy_1.html'
response = requests.get(url, timeout=5, headers=headers)

html = response.text
html = etree.HTML(html)

li_list = html.xpath('//div[@class="tab_box"]/div/ul/li')
for index, li in enumerate(li_list):
    img_url = li.xpath('.//a/img/@data-original')[0]
    urlretrieve(img_url, '{}.jpg'.format(index))