This is a problem caused by https://bugs.python.org/issue13305.

When running python in SerenityOS (https://serenityos.org/), the xmlrpc.client module fails to be imported. This is because the code that decides which format to use for getting 4-digit years, which issues a call to strfmt, raises a ValueError. The ValueError is raised because the second format that is tested yields no output with Serenity's strfmt implementation, so timemodule.strfmt returns NULL.

For reference, this is the code that fails:


_day0 = datetime(1, 1, 1)
if _day0.strftime('%Y') == '0001':      # Mac OS X
    def _iso8601_format(value):
        return value.strftime("%Y%m%dT%H:%M:%S")
elif _day0.strftime('%4Y') == '0001':   # Linux   <-- ValueError
    def _iso8601_format(value):
        return value.strftime("%4Y%m%dT%H:%M:%S")
else:
    def _iso8601_format(value):
        return value.strftime("%Y%m%dT%H:%M:%S").zfill(17)
del _day0

We have a local patch that improves on the current code, which I'll post as a PR now.

New changeset 1c831353816ff699b54e804047a7242a09e98f5b by rtobar in branch 'main':
bpo-45386: Handle strftime's ValueError graciously in xmlrpc.client (GH-28765)
https://github.com/python/cpython/commit/1c831353816ff699b54e804047a7242a09e98f5b

New changeset f40b230df91f29fa4a84c1d127b4eab56a6eda27 by Miss Islington (bot) in branch '3.10':
bpo-45386: Handle strftime's ValueError graciously in xmlrpc.client (GH-28765) (GH-28934)
https://github.com/python/cpython/commit/f40b230df91f29fa4a84c1d127b4eab56a6eda27

New changeset 9210eff61b75edabbe9263df0c4a303fc2149a22 by Miss Islington (bot) in branch '3.9':
bpo-45386: Handle strftime's ValueError graciously in xmlrpc.client (GH-28765) (GH-28935)
https://github.com/python/cpython/commit/9210eff61b75edabbe9263df0c4a303fc2149a22

Thanks, R! ✨ 🍰 ✨