from bs4 import BeautifulSoup
html_doc='''
html_doc = """
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title"><b>The Dormouse's story</b></p>
<p class="story">Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>
<p class="story">...</p>
"""
'''
soup = BeautifulSoup(html_doc)
print(soup.prettify())
那是我的代码。这很容易，但我仍然遇到以下错误：
ImportError：无法导入名称＆＃39; CharsetMetaAttributeValue＆＃39;
有人可以告诉我为什么吗？