Building a Dashboard using Horizon

i have problem with Building a Dashboard using Horizon on centos 7 with this tutorial found it in openstack
https://docs.openstack.org/developer/horizon/tutorials/dashboard.html
i did finish all the steps but for the final setup for run and chuck dashboard with command tox -e runserver -- 0:9000
when i get to the browser and taping http://localhost:9000 i get this message " A server error occurred. Please contact the administrator." and error in line command :

Traceback (most recent call last):
  File "/usr/lib64/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/home/rania/PythonProject/horizon/.tox/runserver/lib/python2.7/site-packages/django/contrib/staticfiles/handlers.py", line 63, in __call__
    return self.application(environ, start_response)
  File "/home/rania/PythonProject/horizon/.tox/runserver/lib/python2.7/site-packages/django/core/handlers/wsgi.py", line 170, in __call__
    self.load_middleware()
  File "/home/rania/PythonProject/horizon/.tox/runserver/lib/python2.7/site-packages/django/core/handlers/base.py", line 52, in load_middleware
    mw_instance = mw_class()
  File "/home/rania/PythonProject/horizon/.tox/runserver/lib/python2.7/site-packages/django/middleware/locale.py", line 24, in __init__
    for url_pattern in get_resolver(None).url_patterns:
  File "/home/rania/PythonProject/horizon/.tox/runserver/lib/python2.7/site-packages/django/core/urlresolvers.py", line 401, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/home/rania/PythonProject/horizon/.tox/runserver/lib/python2.7/site-packages/django/core/urlresolvers.py", line 395, in urlconf_module
    self._urlconf_module = import_module(self.urlconf_name)
  File "/usr/lib64/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/home/rania/PythonProject/horizon/openstack_dashboard/urls.py", line 38, in <module>
    url(r'', include(horizon.urls)),
  File "/home/rania/PythonProject/horizon/.tox/runserver/lib/python2.7/site-packages/django/conf/urls/__init__.py", line 34, in include
    patterns = getattr(urlconf_module, 'urlpatterns', urlconf_module)
  File "/home/rania/PythonProject/horizon/.tox/runserver/lib/python2.7/site-packages/django/utils/functional.py", line 225, in inner
    self._setup()
  File "/home/rania/PythonProject/horizon/.tox/runserver/lib/python2.7/site-packages/django/utils/functional.py", line 376, in _setup
    self._wrapped = self._setupfunc()
  File "/home/rania/PythonProject/horizon/horizon/base.py", line 833, in url_patterns
    return self._urls()[0]
  File "/home/rania/PythonProject/horizon/horizon/base.py", line 844, in _urls
    dash._autodiscover()
  File "/home/rania/PythonProject/horizon/horizon/base.py", line 571, in _autodiscover
    if all([isinstance(i, six.string_types) for i in self.panels]):
TypeError: 'type' object is not iterable

can anyone please help me i'am stacking in this part i want to test and i don't know where is the problem exactly and thanks !!!!!