难以安装Django调试工具栏

我试图安装Django Panels并遇到错误.我使用pip安装 - pip install django-debug-toolbar- 它似乎没问题.但是当我将它添加到我的项目中时:

INSTALLED_APPS = (
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.staticfiles',
    'django.contrib.sites',
    'django.contrib.admin',
    'django.contrib.flatpages',
    'coltrane',
    'markdown',
    'debug_toolbar',
)

然后运行python manage.py syncdb 得到以下错误:

python manage.py syncdb
Traceback (most recent call last):
  File "manage.py", line 10, in 
    execute_from_command_line(sys.argv)
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/Django-1.7.dev20140121103749-py2.7.egg/django/core/management/__init__.py", line 427, in execute_from_command_line
    utility.execute()
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/Django-1.7.dev20140121103749-py2.7.egg/django/core/management/__init__.py", line 391, in execute
    django.setup()
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/Django-1.7.dev20140121103749-py2.7.egg/django/__init__.py", line 21, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/Django-1.7.dev20140121103749-py2.7.egg/django/apps/registry.py", line 105, in populate
    app_config.import_models(all_models)
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/Django-1.7.dev20140121103749-py2.7.egg/django/apps/base.py", line 160, in import_models
    self.models_module = import_module(models_module_name)
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/debug_toolbar/models.py", line 10, in 
    from debug_toolbar.middleware import DebugToolbarMiddleware
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/debug_toolbar/middleware.py", line 13, in 
    from debug_toolbar.toolbar import DebugToolbar
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/debug_toolbar/toolbar.py", line 153, in 
    urlpatterns = DebugToolbar.get_urls()
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/debug_toolbar/toolbar.py", line 147, in get_urls
    for panel_class in cls.get_panel_classes():
  File "/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/debug_toolbar/toolbar.py", line 125, in get_panel_classes
    (panel_module, e))
django.core.exceptions.ImproperlyConfigured: Error importing debug panel debug_toolbar.panels.signals: "cannot import name WEAKREF_TYPES"

我一直在寻找答案,但没有运气.有谁知道这里可能有什么问题？任何帮助将不胜感激.