Traceback (most recent call last):

  File "G:\test\imooc_spider\baike_spider\spider_main.py", line 46, in <module>

    obj_spider.craw(root_url)

  File "G:\test\imooc_spider\baike_spider\spider_main.py", line 24, in craw

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

  File "G:\test\imooc_spider\baike_spider\html_parser.py", line 45, in parse

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

  File "C:\Python27\lib\site-packages\bs4\__init__.py", line 152, in __init__

    % ",".join(features))

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