Help me to solve this issue

[johnfelipe]

Traceback (most recent call last):
  File "/usr/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/contrib/staticfiles/handlers.py", line 67, in __call__
    return self.application(environ, start_response)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/dj_static.py", line 59, in __call__
    return self.application(environ, start_response)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/core/handlers/wsgi.py", line 206, in __call__
    response = self.get_response(request)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 196, in get_response
    response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 234, in handle_uncaught_exception
    if resolver.urlconf_module is None:
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/core/urlresolvers.py", line 341, in urlconf_module
    self._urlconf_module = import_module(self.urlconf_name)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/utils/importlib.py", line 40, in import_module
    __import__(name)
  File "/home/notroot/check-it/project_site/urls.py", line 4, in <module>
    admin.autodiscover()
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/contrib/admin/__init__.py", line 29, in autodiscover
    import_module('%s.admin' % app)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/utils/importlib.py", line 40, in import_module
    __import__(name)
  File "/home/notroot/check-it/promises/admin.py", line 7, in <module>
    from adminsortable.admin import SortableAdminMixin
ImportError: cannot import name SortableAdminMixin
[06/Nov/2015 08:15:42] "GET / HTTP/1.1" 500 59
Traceback (most recent call last):
  File "/usr/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/contrib/staticfiles/handlers.py", line 67, in __call__
    return self.application(environ, start_response)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/dj_static.py", line 59, in __call__
    return self.application(environ, start_response)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/core/handlers/wsgi.py", line 206, in __call__
    response = self.get_response(request)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 196, in get_response
    response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 234, in handle_uncaught_exception
    if resolver.urlconf_module is None:
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/core/urlresolvers.py", line 341, in urlconf_module
    self._urlconf_module = import_module(self.urlconf_name)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/utils/importlib.py", line 40, in import_module
    __import__(name)
  File "/home/notroot/check-it/project_site/urls.py", line 4, in <module>
    admin.autodiscover()
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/contrib/admin/__init__.py", line 29, in autodiscover
    import_module('%s.admin' % app)
  File "/home/notroot/.virtualenvs/check-it/local/lib/python2.7/site-packages/django/utils/importlib.py", line 40, in import_module
    __import__(name)
  File "/home/notroot/check-it/promises/admin.py", line 7, in <module>
    from adminsortable.admin import SortableAdminMixin
ImportError: cannot import name SortableAdminMixin