安装 
pip install lxml
代码示例 

from lxml import etree

text = """
<html>
    <head>
        <title>这是标题</title>
    </head>
    <body>
        <div>这是内容</div>
    </body>
</html>"""

html = etree.HTML(text)

# 使用xpath解析
titles = html.xpath("//title")
for title in titles:
    print(title.text)

# 使用css解析
titles = html.cssselect("title")
for title in titles:
    print(title.text)