Scripts crash when called with -v option in python 3.8.
Cannot say about other versions, except my comment below in **Expected Results**:
```
Release version: 5.0.1.dev0
requests version: 2.24.0
cacerts: /home/user/anaconda3/lib/python3.8/site-packages/certifi/cacert.pem
certificate test: ok
Python: 3.8.3 (default, Jul 2 2020, 16:21:59)
```
**Steps to Reproduce: **
python scripts/listpages.py -start:A -v
**Actual Results:**
```
user@pc:~/python/core$ python scripts/listpages.py -start:A -v
=== Pywikibot framework v5.0.1.dev0 -- Logging header ===
COMMAND: ['scripts/listpages.py', '-start:A', '-v']
DATE: 2020-10-19 20:01:07.414882 UTC
VERSION: [ssh] pywikibot-core.git (4cdf2f0, g13425, 2020/10/19, 17:05:17, n/a)
SYSTEM: posix.uname_result(sysname='Linux', nodename='pc', release='4.15.0-117-generic', version='#118-Ubuntu SMP Fri Sep 4 20:02:41 UTC 2020', machine='x86_64')
CONFIG FILE DIR: /home/user/.pywikibot
PACKAGES:
Traceback (most recent call last):
File "scripts/listpages.py", line 284, in <module>
main()
File "scripts/listpages.py", line 190, in main
local_args = pywikibot.handle_args(args)
File "/home/user/python/core/pywikibot/bot.py", line 850, in handle_args
pywikibot.Site()
File "/home/user/python/core/pywikibot/tools/__init__.py", line 1450, in wrapper
return obj(*__args, **__kw)
File "/home/user/python/core/pywikibot/__init__.py", line 1203, in Site
debug("Instantiated %s object '%s'"
File "/home/user/python/core/pywikibot/logging.py", line 178, in debug
logoutput(text, decoder, newline, DEBUG, layer, **kwargs)
File "/home/user/python/core/pywikibot/logging.py", line 76, in logoutput
_init()
File "/home/user/python/core/pywikibot/logging.py", line 35, in _init
init_routine()
File "/home/user/python/core/pywikibot/bot.py", line 346, in init_handlers
writelogheader()
File "/home/user/python/core/pywikibot/bot.py", line 392, in writelogheader
packages = version.package_versions(check_package_list)
File "/home/user/python/core/pywikibot/version.py", line 519, in package_versions
if os.path.normcase(package.__file__).startswith(
File "/home/user/anaconda3/lib/python3.8/posixpath.py", line 54, in normcase
return os.fspath(s)
TypeError: expected str, bytes or os.PathLike object, not NoneType
Found 1 wikisource:en processes running, including this one.
Dropped throttle(s).
Closing network session.
CRITICAL: Exiting due to uncaught exception <class 'TypeError'>
Network session closed.
```
The offending package is (there might be others)
```
{'__name__': 'mpl_toolkits', '__doc__': None, '__package__': 'mpl_toolkits', '__loader__': <_frozen_importlib_external._NamespaceLoader object at 0x7f03eb523f10>, '__spec__': ModuleSpec(name='mpl_toolkits', loader=<_frozen_importlib_external._NamespaceLoader object at 0x7f03eb523f10>, submodule_search_locations=_NamespacePath(['/home/user/anaconda3/lib/python3.8/site-packages/mpl_toolkits'])), '__file__': None, '__path__': _NamespacePath(['/home/user/anaconda3/lib/python3.8/site-packages/mpl_toolkits'])}
```
where:
```
__file__': None
```
**Expected Results:**
The script should work, e.g. in T265928 (python3.6), it is possible to see:
```
PACKAGES:
...
mpl_toolkits ([path unknown]) = ??
mwoauth (/srv/paws/lib/python3.6/site-packages/mwoauth/) = 0.3.7
...
```