python - Reverse for 'userlist' with arguments '()' and keyword arguments '{}' not found. 0 pattern(s) tried: [] -

views.py:

from .models import classname .serializers import classserializer, userserializer rest_framework import generics, permissions, renderers rest_framework.decorators import api_view .permissions import isownerorreadonly rest_framework.response import response django.contrib.auth.models import user rest_framework.reverse import reverse   @api_view(('get',)) def api_root(request, format=none):     return response({         'users': reverse('userlist', request=request, format=format),         'fab': reverse('classlist', request=request, format=format)     }) class classlist(generics.listcreateapiview):     queryset = classname.objects.all()     serializer_class = classserializer     permission_classes = (permissions.isauthenticatedorreadonly,)      def perform_create(self, serializer):         serializer.save(owner=self.request.user)  class classdetail(generics.retrieveupdatedestroyapiview):     queryset = user.objects.all()     serializer_class = userserializer     permission_classes = (permissions.isauthenticatedorreadonly, isownerorreadonly,)  class userlist(generics.listapiview):     queryset = user.objects.all()     serializer_class = userserializer  class userdetail(generics.retrieveapiview):     queryset = user.objects.all()     serializer_class = userserializer  class classhighlight(generics.genericapiview):     queryset = classname.objects.all()     renderer_classes = (renderers.statichtmlrenderer,)  def get(self, request, *args, **kwargs):     fab = self.get_object()     return response(fab.highlighted) 

urls.py:

from django.conf.urls import url rest_framework import renderers . import views  urlpatterns = [     url(r'^$', views.api_root),     url(r'^classlist/$', views.classlist.as_view(), name = 'classlist'),     url(r'^class/(?p<pk>[0-9]+)/highlight/$', views.classhighlight.as_view()),     url(r'^classdetail/(?p<pk>[0-9]+)/$', views.classdetail.as_view(), name = 'classdetail'),     url(r'^userlist/$', views.userlist.as_view(), name='userlist'),     url(r'^userdetail/$', views.userdetail.as_view(), name='userdetail'), ] 

here full traceback:

environment:   request method: request url: http://127.0.0.1:8000/how/  django version: 1.8.3 python version: 3.4.3 installed applications: ('django.contrib.admin',  'django.contrib.auth',  'django.contrib.contenttypes',  'django.contrib.sessions',  'django.contrib.messages',  'django.contrib.staticfiles',  'rest_framework',  'fab')  installed middleware: ('django.contrib.sessions.middleware.sessionmiddleware',  'django.middleware.common.commonmiddleware',  'django.middleware.csrf.csrfviewmiddleware',  'django.contrib.auth.middleware.authenticationmiddleware',  'django.contrib.auth.middleware.sessionauthenticationmiddleware',  'django.contrib.messages.middleware.messagemiddleware',  'django.middleware.clickjacking.xframeoptionsmiddleware',  'django.middleware.security.securitymiddleware')   traceback: file "c:\users\user\dem\venv\lib\site-     packages\django\core\handlers\base.py" in get_response 132.                     response = wrapped_callback(request, *callback_args, **callback_kwargs) file "c:\users\user\dem\venv\lib\site-packages\django\views\decorators\csrf.py" in wrapped_view 58.         return view_func(*args, **kwargs) file "c:\users\user\dem\venv\lib\site-packages\django\views\generic\base.py" in view 71.             return self.dispatch(request, *args, **kwargs) file "c:\users\user\dem\venv\lib\site-packages\rest_framework\views.py" in dispatch 456.             response = self.handle_exception(exc) file "c:\users\user\dem\venv\lib\site-packages\rest_framework\views.py" in dispatch 453.             response = handler(request, *args, **kwargs) file "c:\users\user\dem\venv\lib\site-packages\rest_framework\decorators.py" in handler 50.             return func(*args, **kwargs) file "c:\users\user\dem\try\howsthat\fab\views.py" in api_root 16.         'users': reverse('userlist', request=request, format=format), file "c:\users\user\dem\venv\lib\site-packages\rest_framework\reverse.py" in reverse 26.     return _reverse(viewname, args, kwargs, request, format, **extra) file "c:\users\user\dem\venv\lib\site-packages\rest_framework\reverse.py" in _reverse 37.     url = django_reverse(viewname, args=args, kwargs=kwargs, **extra) file "c:\users\user\dem\venv\lib\site-packages\django\core\urlresolvers.py" in reverse 579.     return force_text(iri_to_uri(resolver._reverse_with_prefix(view, prefix, *args, **kwargs))) file "c:\users\user\dem\venv\lib\site-packages\django\core\urlresolvers.py" in _reverse_with_prefix 496.                              (lookup_view_s, args, kwargs, len(patterns), patterns))  exception type: noreversematch @ /how/ exception value: reverse 'userlist' arguments '()' , keyword arguments '{}' not found. 0 pattern(s) tried: [] 

when i'm trying add 'api_root' view in views.py file shows above error. i'm using namespacing in urls.py have no idea why throws error?

please me resolve it....

thanks! in advance....

try including namespace using when include urls.py.

reverse('how:userlist', request=request, format=format),