Otherwise we get this in setuptools build with pytest 6.2+:
> warnings.warn(pytest.PytestUnraisableExceptionWarning(msg))
E pytest.PytestUnraisableExceptionWarning: Exception ignored in: <_io.FileIO [closed]>
E
E Traceback (most recent call last):
E File "/usr/lib/python3.9/site-packages/pytz/__init__.py", line 522, in <module>
E common_timezones = [l.split()[2]
E ResourceWarning: unclosed file <_io.TextIOWrapper name='/usr/share/zoneinfo/zone.tab' mode='r' encoding='UTF-8'>
/usr/lib/python3.9/site-packages/_pytest/unraisableexception.py:78: PytestUnraisableExceptionWarning
