【Django】ModuleNotFoundError: No module named 'books_ordersschool'

Unhandled exception in thread started by <function check_errors.<locals>.wrapper at 0x0000027C8359E950>
Traceback (most recent call last):
File "C:\Users\Admin\Envs\python36env\lib\site-packages\django\utils\autoreload.py", line 225, in wrapper
fn(*args, **kwargs)
File "C:\Users\Admin\Envs\python36env\lib\site-packages\django\core\management\commands\runserver.py", line 109, in inner_run
autoreload.raise_last_exception()
File "C:\Users\Admin\Envs\python36env\lib\site-packages\django\utils\autoreload.py", line 248, in raise_last_exception
raise _exception[1]
File "C:\Users\Admin\Envs\python36env\lib\site-packages\django\core\management\__init__.py", line 337, in execute
autoreload.check_errors(django.setup)()
File "C:\Users\Admin\Envs\python36env\lib\site-packages\django\utils\autoreload.py", line 225, in wrapper
fn(*args, **kwargs)
File "C:\Users\Admin\Envs\python36env\lib\site-packages\django\__init__.py", line 24, in setup
apps.populate(settings.INSTALLED_APPS)
File "C:\Users\Admin\Envs\python36env\lib\site-packages\django\apps\registry.py", line 89, in populate
app_config = AppConfig.create(entry)
File "C:\Users\Admin\Envs\python36env\lib\site-packages\django\apps\config.py", line 90, in create
module = import_module(entry)
File "C:\Users\Admin\Envs\python36env\lib\importlib\__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'books_ordersschool'

刚刚报了一个奇怪的错误，说找不到books_ordersschool这个module。明明这里没有定义这个，纳闷是哪里引用了，后来发现，原来是settings里面的

INSTALLED_APPS里

'books_orders',#这里漏了一个逗号！！！
'school',