https://github.com/Naddiseo/python-core-dump reproducer no longer works on Python 3.10.

# in Python source code directory
git clone https://github.com/Naddiseo/python-core-dump
make
./python -m venv ENV
ENV/bin/python -m pip install -r python-core-dump/requirements.txt 
cd python-core-dump/
../ENV/bin/python manage.py migrate

Output:
---
/home/vstinner/python/master/ENV/lib/python3.10/site-packages/django/db/models/sql/query.py:11: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.10 it will stop working
  from collections import Counter, Iterator, Mapping, OrderedDict
/home/vstinner/python/master/ENV/lib/python3.10/site-packages/django/core/paginator.py:101: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.10 it will stop working
  class Page(collections.Sequence):
Traceback (most recent call last):
  File "/home/vstinner/python/master/python-core-dump/manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/home/vstinner/python/master/ENV/lib/python3.10/site-packages/django/core/management/__init__.py", line 367, in execute_from_command_line
    utility.execute()
  File "/home/vstinner/python/master/ENV/lib/python3.10/site-packages/django/core/management/__init__.py", line 341, in execute
    django.setup()
  File "/home/vstinner/python/master/ENV/lib/python3.10/site-packages/django/__init__.py", line 27, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/home/vstinner/python/master/ENV/lib/python3.10/site-packages/django/apps/registry.py", line 108, in populate
    app_config.import_models(all_models)
  File "/home/vstinner/python/master/ENV/lib/python3.10/site-packages/django/apps/config.py", line 199, in import_models
    self.models_module = import_module(models_module_name)
  File "/home/vstinner/python/master/Lib/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1037, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1014, in _find_and_load
  File "<frozen importlib._bootstrap>", line 993, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 687, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 831, in exec_module
  File "<frozen importlib._bootstrap>", line 235, in _call_with_frames_removed
  File "/home/vstinner/python/master/ENV/lib/python3.10/site-packages/django/contrib/auth/models.py", line 4, in <module>
    from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
  File "/home/vstinner/python/master/ENV/lib/python3.10/site-packages/django/contrib/auth/base_user.py", line 52, in <module>
    class AbstractBaseUser(models.Model):
RuntimeError: __class__ not set defining 'AbstractBaseUser' as <class 'django.contrib.auth.base_user.AbstractBaseUser'>. Was __classcell__ propagated to type.__new__?
---