'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'app_test.apps.PagesConfig',
]```

Error:

```ModuleNotFoundError: No module named 'app_test.apps.PagesConfig'; 'app_test.apps' is not a package```