AttributeError: module 'html5lib.treebuilders.etree' has no attribute 'getETreeModule'

Question

Suggestions please, thanks :)

pip list --outdated --format=freeze

Gives the following error:

ERROR: Exception:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/pip/_internal/cli/base_command.py", line 223, in _main
    status = self.run(options, args)
  File "/usr/lib/python3/dist-packages/pip/_internal/commands/list.py", line 175, in run
    packages = self.get_outdated(packages, options)
  File "/usr/lib/python3/dist-packages/pip/_internal/commands/list.py", line 184, in get_outdated
    return [
  File "/usr/lib/python3/dist-packages/pip/_internal/commands/list.py", line 184, in <listcomp>
    return [
  File "/usr/lib/python3/dist-packages/pip/_internal/commands/list.py", line 237, in iter_packages_latest_infos
    for dist in map_multithread(latest_info, packages):
  File "/usr/lib/python3.9/multiprocessing/pool.py", line 870, in next
    raise value
  File "/usr/lib/python3.9/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
  File "/usr/lib/python3/dist-packages/pip/_internal/commands/list.py", line 214, in latest_info
    all_candidates = finder.find_all_candidates(dist.key)
  File "/usr/lib/python3/dist-packages/pip/_internal/index/package_finder.py", line 825, in find_all_candidates
    package_links = self.process_project_url(
  File "/usr/lib/python3/dist-packages/pip/_internal/index/package_finder.py", line 793, in process_project_url
    page_links = list(parse_links(html_page))
  File "/usr/lib/python3/dist-packages/pip/_internal/index/collector.py", line 324, in wrapper_wrapper
    return list(fn(page))
  File "/usr/lib/python3/dist-packages/pip/_internal/index/collector.py", line 335, in parse_links
    document = html5lib.parse(
  File "/usr/share/python-wheels/html5lib-1.1-py2.py3-none-any.whl/html5lib/html5parser.py", line 44, in parse
    tb = treebuilders.getTreeBuilder(treebuilder)
  File "/usr/share/python-wheels/html5lib-1.1-py2.py3-none-any.whl/html5lib/treebuilders/__init__.py", line 85, in getTreeBuilder
    return etree.getETreeModule(implementation, **kwargs).TreeBuilder
AttributeError: module 'html5lib.treebuilders.etree' has no attribute 'getETreeModule'

Answer 1

I solved this problem updating pip, i updated from pip 20.3.4 to 21.3 so just type:

pip install pip -U

Seems like there is some bug in pip itself.