len() of unsized object这个报错是什么原因么
File "D:\SOFTWARE\beautifulsoup4-4.6.0\bs4\__init__.py", line 190, in __init__
if hasattr(markup, 'read'):
File "D:\eclipse\workspace\pachong\baike\main.py", line 37, in <module>
obj_spider.craw(root_url)
File "D:\eclipse\workspace\pachong\baike\main.py", line 22, in craw
new_urls, new_data = self.parser.parse(new_url,html_cont)
File "D:\eclipse\workspace\pachong\baike\html_parser.py", line 43, in parse
soup = BeautifulSoup(html_cont, 'html.parser', from_encoding='utf-8')
TypeError: len() of unsized object对应行数代码已经贴在每句提示下面了，老师帮忙看看
