想获取廖雪峰python教程网站的内容练练手，发现有的章节能返回数据，但到Python基础这一章开始返回的都是None，没明白问题出在哪，求教
错误如下：
Traceback (most recent call last):
File "scraping_the_tutorial.py", line 36, in
get_urls()
File "scraping_the_tutorial.py", line 34, in get_urls
parse_url_to_html(a.attrs["href"],a.get_text())
File "scraping_the_tutorial.py", line 23, in parse_url_to_html
content = content.get_text()
AttributeError: 'NoneType' object has no attribute 'get_text'
代码如下：
import requests
from bs4 import BeautifulSoup
# session对象
session = requests.Session()
# 用于表明自己是何浏览器以及指定返回数据格式
headers = {"User-Agent":"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 \
(KHTML, like Gecko) Chrome/64.0.3282.186 Safari/537.36",
"Accept":"text/html,application/xhtml+xml,application/xml;\
q=0.9,image/webp,*/*;q=0.8"}
# 要获取数据的网站
def parse_url_to_html(url,file_name):
# 通过get(url,headers)函数来接受返回的数据
req = session.get("https://www.liaoxuefeng.com"+url, headers=headers)
# 用bs解析便于处理数据,第二个参数是何种解析方法
bsObj = BeautifulSoup(req.text,"html.parser")
# 获取教程内容，在class为x-wiki-content x-main-content里
content = bsObj.find("div",{"class":"x-content"})
# 用str不用getText是因为有时候有None值
# 上面错了，是因为服务器反爬机制返回HTTP error503
print(content)
content = content.get_text()
# 存到txt文件夹中
with open("txt/%s.txt" % file_name,'w') as f:
f.write(content)
def get_urls():
html = session.get("https://www.liaoxuefeng.com/wiki/0014316089557264a6b348958f449949df42a6d3a2e542c000", \
headers=headers)
bsObj = BeautifulSoup(html.text,"html.parser")
directory = bsObj.find("ul",{"id":"x-wiki-index"})
for a in directory.findAll("a",{"class":"x-wiki-index-item"}):
parse_url_to_html(a.attrs["href"],a.get_text())
if __name__ == "__main__":
get_urls()
