crawl 1 : https://baike.baidu.com/item/Python/407313?fr=aladdin

Traceback (most recent call last):

  File "D:\Eclipse\project\crawl\school\spider_main.py", line 39, in <module>

    obj_spider.craw(root_url)

  File "D:\Eclipse\project\crawl\school\spider_main.py", line 23, in craw

    new_urls, new_data = self.parser.parse(new_url, html_cont)

  File "D:\Eclipse\project\crawl\school\html_parser.py", line 41, in parse

    soup = BeautifulSoup(html_cont, 'html_parser', from_encoding='utf-8')

  File "build\bdist.win-amd64\egg\bs4\__init__.py", line 165, in __init__

bs4.FeatureNotFound: Couldn't find a tree builder with the features you requested: html_parser. Do you need to install a parser library?

啥原因