爬虫运行程序后得到CSV文件中无任何数据

在爬取豆瓣时导不出数据

import requests
import re
import csv

url = "https://movie.douban.com/top250"
headers = {
    "user-agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko)Chrome/86.0.4240.198 Safari/537.36"}
resp = requests.get(url, headers=headers)
page_content = resp.text
# 解析数据
obj = re.compile(r'<li>.*?<div class="item">.*?<span class="title">(?P<name>.*?)'
                 r'</span>.*?<p class="">.*?<br>(?P<year>.*?)&nbsp.*?<span'
                 r'class="rating_num" property="v:average">(?P<score>.*?)</span>.*?'
                 r'<span>(?P<num>.*?)评价</span>', re.S)
# 开始匹配
result = obj.finditer(page_content)
f = open("data.csv", mode="w",encoding=("utf-8"))
csvwriter = csv.writer(f)
for it in result:
    dic = it.groupdict()
    dic['year'] = dic['year'].strip()
    csvwriter.writerow(dic.values())
f.close
print("over!")

compile中 第二行的最末<span后要加一个空格