今天遇到一个django的问题，如下：

Traceback (most recent call last):
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/core/servers/basehttp.py", line 45, in get_internal_wsgi_application
    return import_string(app_path)
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/utils/module_loading.py", line 17, in import_string
    module = import_module(module_path)
  File "/usr/lib/python3.6/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 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/home/lx/PycharmProjects/blogs/new_blogs/new_blogs/wsgi.py", line 16, in <module>
    application = get_wsgi_application()
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/core/wsgi.py", line 13, in get_wsgi_application
    return WSGIHandler()
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/core/handlers/wsgi.py", line 127, in __init__
    self.load_middleware()
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 40, in load_middleware
    middleware = import_string(middleware_path)
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/utils/module_loading.py", line 17, in import_string
    module = import_module(module_path)
  File "/usr/lib/python3.6/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 941, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 941, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 950, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'corsheaders.middleware.CorsMiddlewaredjango'; 'corsheaders.middleware' is not a package

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.6/threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/utils/autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/core/management/commands/runserver.py", line 138, in inner_run
    handler = self.get_handler(*args, **options)
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/contrib/staticfiles/management/commands/runserver.py", line 27, in get_handler
    handler = super().get_handler(*args, **options)
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/core/management/commands/runserver.py", line 65, in get_handler
    return get_internal_wsgi_application()
  File "/home/lx/PycharmProjects/blogs/venv/lib/python3.6/site-packages/django/core/servers/basehttp.py", line 50, in get_internal_wsgi_application
    ) from err
django.core.exceptions.ImproperlyConfigured: WSGI application 'new_blogs.wsgi.application' could not be loaded; Error importing module.

问题是我在django的中间件配置中

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    "corsheaders.middleware.CorsMiddleware"
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

在corsherders中少加了一个逗号，才导致这个问题，拼写需谨慎