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

Question

最近，我将Django framework的版本从2.0.6升级到3.0，在调用python manage.py shell命令后，突然出现了以下异常：

重要错误：无法从django.utils导入名称六（/path-to-project/project/venv/lib/python3.7/site-包/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

类似问题：

我读了这个问题和这个django-3.0发行说明，但是这些资源帮不了我。