配置不当：您必须在访问设置之前定义环境变量 DJANGO_SETTINGS_MODULE 或调用 settings.configure()

我正在try 配置我的Django项目以部署到Heroku.我收到以下错误，但我真的不知道如何修复它.

以下是full traceback和错误:

22:46:15 web.1  | Traceback (most recent call last):
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/gunicorn/arbiter.py", line 495, in spawn_worker
22:46:15 web.1  |     worker.init_process()
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/gunicorn/workers/base.py", line 106, in init_process
22:46:15 web.1  |     self.wsgi = self.app.wsgi()
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/gunicorn/app/base.py", line 114, in wsgi
22:46:15 web.1  |     self.callable = self.load()
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 62, in load
22:46:15 web.1  |     return self.load_wsgiapp()
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 49, in load_wsgiapp
22:46:15 web.1  |     return util.import_app(self.app_uri)
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/gunicorn/util.py", line 354, in import_app
22:46:15 web.1  |     __import__(module)
22:46:15 web.1  |   File "/Users/nir/nirla/nirla/wsgi.py", line 12, in <module>
22:46:15 web.1  |     from dj_static import Cling
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/dj_static.py", line 7, in <module>
22:46:15 web.1  |     from django.contrib.staticfiles.handlers import StaticFilesHandler as DebugHandler
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/django/contrib/staticfiles/handlers.py", line 8, in <module>
22:46:15 web.1  |     from django.contrib.staticfiles.views import serve
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/django/contrib/staticfiles/views.py", line 13, in <module>
22:46:15 web.1  |     from django.views import static
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/django/views/static.py", line 96, in <module>
22:46:15 web.1  |     template_translatable = ugettext_noop("Index of %(directory)s")
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/django/utils/translation/__init__.py", line 65, in gettext_noop
22:46:15 web.1  |     return _trans.gettext_noop(message)
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/django/utils/translation/__init__.py", line 52, in __getattr__
22:46:15 web.1  |     if settings.USE_I18N:
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/django/conf/__init__.py", line 54, in __getattr__
22:46:15 web.1  |     self._setup(name)
22:46:15 web.1  |   File "/Users/nir/nirla/venv/lib/python2.7/site-packages/django/conf/__init__.py", line 47, in _setup
22:46:15 web.1  |     % (desc, ENVIRONMENT_VARIABLE))
22:46:15 web.1  | ImproperlyConfigured: Requested setting USE_I18N, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings.

这是我的wsgi.py号文件:

import os
from django.core.wsgi import get_wsgi_application
from dj_static import Cling

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "nirla.settings") #nirla is the name of the project


application = Cling(get_wsgi_application())

如果相关的话，我的manage.py号档案:

import os
import sys

    if __name__ == "__main__":
        os.environ.setdefault("DJANGO_SETTINGS_MODULE", "nirla.settings")
    
        from django.core.management import execute_from_command_line
    
        execute_from_command_line(sys.argv)

有人能理解这里的问题吗？如果是这样的话，你能解释一下是怎么回事吗？