pip3 on python3.9 fails on 'HTMLParser' object has no attribute 'unescape'

Question

After installing (ubuntu) python3.9, installing some packages with pip failes on:

    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/usr/lib/python3/dist-packages/setuptools/__init__.py", line 14, in <module>
        from setuptools.dist import Distribution, Feature
      File "/usr/lib/python3/dist-packages/setuptools/dist.py", line 24, in <module>
        from setuptools.depends import Require
      File "/usr/lib/python3/dist-packages/setuptools/depends.py", line 7, in <module>
        from .py33compat import Bytecode
      File "/usr/lib/python3/dist-packages/setuptools/py33compat.py", line 54, in <module>
        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.

Answer 1

After some trial and error I upgraded, pip, distlib and setuptools and it solved it. Not sure which of those is causing it. (On the last two I found issues 1 2 of other sites) It is caused by removing unescape from HTMLParser in python3.9, which seems to break setuptools.

pip3 install --upgrade setuptools

If it does not work, try also:

pip3 install --upgrade pip
pip3 install --upgrade distlib