Django 1.4，mongoengine.django.sessions：无法导入名称Connection

Question

我是Django的新手，并且在其他人的代码中工作了一段时间没有用过。

  

python manage.py syncdb --settings = mysite.settings_local

File "/Users/hkwik/.virtualenvs/env/lib/python2.7/site-packages/south/management/commands/__init__.py", line 10, in <module>
    import django.template.loaders.app_directories
File "/Users/hkwik/.virtualenvs/env/lib/python2.7/site-packages/django/template/loaders/app_directories.py", line 23, in <module>
    raise ImproperlyConfigured('ImportError %s: %s' % (app, e.args[0]))
django.core.exceptions.ImproperlyConfigured: ImportError mongoengine.django.sessions: cannot import name Connection

当前依赖关系：

BeautifulSoup==3.2.1
blinker==1.3
cffi==0.9.2
cryptography==0.8.2
cssselect==0.9.1
Django==1.4
django-bcrypt==0.9.2
django-debug-toolbar==1.3.0
django-form-utils==1.0.2
django-mongo-sessions==0.0.3
django-mumblr==0.1
django-social-auth==0.7.28
ecdsa==0.13
enum34==1.0.4
Fabric==1.10.1
gunicorn==0.14.2
httplib2==0.9.1
lxml==3.4.4
mongo==0.2.0
mongodbforms==0.3
mongoengine==0.6.3
MySQL-python==1.2.5
oauth2==1.5.211
paramiko==1.15.2
PIL==1.1.7
psycopg2==2.6
py-bcrypt==0.4
pyasn1==0.1.7
pycparser==2.12
pycrypto==2.6.1
pymongo==3.0.1
pyOpenSSL==0.15.1
python-openid==2.2.5
queuelib==1.2.2
redis==2.10.3
Scrapy==0.24.6
six==1.9.0
sorl-thumbnail==3.2.5
South==1.0.2
sqlparse==0.1.15
Twisted==15.1.0
w3lib==1.11.0
zope.interface==4.1.2

在settings.py中：

INSTALLED_APPS = (
...
mongoengine.django.sessions
...
)

SESSION_ENGINE = 'mongoengine.django.sessions'

不确定这里发生了什么。谁能给我一些指示？