title: pip3 on python3.9 fails on 'HTMLParser' object has no attribute 'unescape'
body: <p>After installing (ubuntu) python3.9, installing some packages with pip failes on:</p>
  <pre><code>    Traceback (most recent call last):
        File &quot;&lt;string&gt;&quot;, line 1, in &lt;module&gt;
        File &quot;/usr/lib/python3/dist-packages/setuptools/__init__.py&quot;, line 14, in &lt;module&gt;
          from setuptools.dist import Distribution, Feature
        File &quot;/usr/lib/python3/dist-packages/setuptools/dist.py&quot;, line 24, in &lt;module&gt;
          from setuptools.depends import Require
        File &quot;/usr/lib/python3/dist-packages/setuptools/depends.py&quot;, line 7, in &lt;module&gt;
          from .py33compat import Bytecode
        File &quot;/usr/lib/python3/dist-packages/setuptools/py33compat.py&quot;, line 54, in &lt;module&gt;
          unescape = getattr(html, 'unescape', html_parser.HTMLParser().unescape)
      AttributeError: 'HTMLParser' object has no attribute 'unescape'
      ----------------------------------------
  ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
  </code></pre>