ImportError：无法从“ django.utils”导入名称“ six”

Question

目前，我已经将Django的版本从升级2.0.6到，3.0并且在调用python manage.py shellcommand时突然出现以下错误：

ImportError: cannot import name 'six' from 'django.utils' (/path-to-project/project/venv/lib/python3.7/site-packages/django/utils/init.py)

完整跟踪：

Traceback (most recent call last):
  File "manage.py", line 13, in <module>
    execute_from_command_line(sys.argv)
  File "/path-to-project/project/venv/lib/python3.7/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "/path-to-project/project/venv/lib/python3.7/site-packages/django/core/management/__init__.py", line 377, in execute
    django.setup()
  File "/path-to-project/project/venv/lib/python3.7/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/path-to-project/project/venv/lib/python3.7/site-packages/django/apps/registry.py", line 91, in populate
    app_config = AppConfig.create(entry)
  File "/path-to-project/project/venv/lib/python3.7/site-packages/django/apps/config.py", line 90, in create
    module = import_module(entry)
  File "/usr/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/path-to-project/project/venv/lib/python3.7/site-packages/corsheaders/__init__.py", line 1, in <module>
    from .checks import check_settings  # noqa: F401
  File "/path-to-project/project/venv/lib/python3.7/site-packages/corsheaders/checks.py", line 7, in <module>
    from django.utils import six

Answer 1

Django 3.0.0发行说明指定删除了某些私有的Python 2兼容性API。其中有django.utils.six。

对于此错误，@ WillemVanOnsem特别指出该模块corsheaders正在引用该模块。

对于遇到相同问题的其他人，查看stacktrace的最后一行上的文件路径可以帮助识别有问题的模块。我看到的另一个例子是：

...
File "/path/to/project/venv/lib/python3.8/site-packages/parler/utils/conf.py", line 10, in <module>
    from django.utils import six
ImportError: cannot import name 'six' from 'django.utils' (/path/to/project/venv/lib/python3.8/site-packages/django/utils/__init__.py)

在这种情况下，导致问题的模块为parler。希望这对遇到此问题的其他人有所帮助。