`isinstance(django_settings, type)` triggers ImproperlyConfigured, although settings are not really accessed

[Daniel Hahler]

Checking if django.conf.settings is a class should not trigger an exception, but the following code triggers ImproperlyConfigured already:

from django.conf import settings as django_settings
isinstance(django_settings, type)

(via ​https://github.com/pytest-dev/pytest/issues/4266)

[Simon Charette]

As mentioned on the linked PR this has little to do with the isinstance check; accessing django.conf.settings attributes (in this case __class__ through isinstance) is prohibited until ​settings are configured.