尝试运行时出现以下错误：
from braces.views import LoginRequiredMixin, PermissionRequiredMixin, AnonymousRequiredMixin
但是，在开发环境中一切正常，在我的生产环境中也是如此。django-braces位于virtualenv。
是否有人遇到此错误或知道导致AnonymousRequiredMixin导致问题的原因？
[Tue Jul 15 14:36:08 2014] [error] [client 70.180.246.22] url(r'', include('core.urls', namespace='core')),
[Tue Jul 15 14:36:08 2014] [error] [client 70.180.246.22] File "/usr/local/lib/python2.7/dist-packages/django/conf/urls/__init__.py", line 25, in include
[Tue Jul 15 14:36:08 2014] [error] [client 70.180.246.22] urlconf_module = import_module(urlconf_module)
[Tue Jul 15 14:36:08 2014] [error] [client 70.180.246.22] File "/usr/local/lib/python2.7/dist-packages/django/utils/importlib.py", line 35, in import_module
[Tue Jul 15 14:36:08 2014] [error] [client 70.180.246.22] __import__(name)
[Tue Jul 15 14:36:08 2014] [error] [client 70.180.246.22] File "/home/aaron/public_html/learnrealsql.com/asql/core/urls.py", line 3, in <module>
[Tue Jul 15 14:36:08 2014] [error] [client 70.180.246.22] from core import views
[Tue Jul 15 14:36:08 2014] [error] [client 70.180.246.22] File "/home/aaron/public_html/learnrealsql.com/asql/core/views.py", line 22, in <module>
[Tue Jul 15 14:36:08 2014] [error] [client 70.180.246.22] from braces.views import LoginRequiredMixin, PermissionRequiredMixin, AnonymousRequiredMixin
[Tue Jul 15 14:36:08 2014] [error] [client 70.180.246.22] ImportError: cannot import name AnonymousRequiredMixin
修改
我正在使用：
Django 1.6.5
Python 3.3
django-braces 1.4.0