title: url() got an unexpected keyword argument 'namespace'
body: <p>New to Django here, so pardon the rookie question...</p>
  
  <p>I'm getting the <code>url() got an unexpected keyword argument 'namespace'</code> error when I try to call on the <code>reverse</code> function. Tried a few different ways to fix it but nothing seems to be working. Any advice would be greatly appreciated. Please see my code below:</p>
  
  <pre><code>TypeError at /comments/topic-create/
  url() got an unexpected keyword argument 'namespace'
  Request Method: POST
  Request URL:    http://127.0.0.1:8000/comments/topic-create/
  Django Version: 1.8.6
  Exception Type: TypeError
  Exception Value:    
  url() got an unexpected keyword argument 'namespace'
  </code></pre>
  
  <p><strong>models.py</strong></p>
  
  <pre><code>from django.db import models
  from django.conf import settings
  from django.utils.text import slugify
  from django.core.urlresolvers import reverse
  
  class Topic(models.Model):
      title = models.CharField(max_length=50)
      stock = models.ManyToManyField(Stock)
      slug = models.SlugField(max_length=200, blank=True)
      created = models.DateField(auto_now_add=True,
                                 db_index=True)
  
      def __str__(self):
          return self.title
  
      def save(self, *args, **kwargs):
          if not self.slug:
              self.slug = slugify(self.title)
              super(Topic, self).save(*args, **kwargs)
  
      def get_absolute_url(self):
          return reverse('comments:topic_detail', args=[self.id, self.slug])
  </code></pre>
  
  <p><strong>forms.py</strong></p>
  
  <pre><code>from django import forms
  from .models import Topic
  
  class TopicCreateForm(forms.ModelForm):
      class Meta:
          model = Topic
          fields = ('__all__')
  </code></pre>
  
  <p><strong>views.py</strong></p>
  
  <pre><code>from django.shortcuts import render, redirect, get_object_or_404
  from django.contrib.auth.decorators import login_required
  from .forms import TopicCreateForm
  from django.contrib import messages
  from .models import Stock, Topic, Comment
  # from django.core.urlresolvers import reverse_lazy
  
  @login_required
  def topic_create(request):
      if request.method == 'POST':
          form = TopicCreateForm(data=request.POST)
          if form.is_valid():
              cd = form.cleaned_data
              new_item = form.save(commit=False)
              new_item.user = request.user
              new_item.save()
              messages.success(request, 'Topic added successfully')
              # redirect to new created topic detail view
              return redirect(new_item.get_absolute_url())
      else:
          form = TopicCreateForm(data=request.GET)
  
      return render(request,
                    'comments/comment/topic-create.html',
                    {'section': 'topic',
                     'form': form})
  
  def topic_detail(request, namespace, id, slug):
      topic = get_object_or_404(Topic, id=id, slug=slug)
      return render(request,
                    'comments/comment/topic-detail.html',
                    {'section': 'topic',
                     'topic': topic})
  </code></pre>
  
  <p><strong>comments/urls.py</strong></p>
  
  <pre><code>from django.conf.urls import url
  from . import views
  
  urlpatterns = [
      url(r'^topic-create/$', views.topic_create, name='create-topic'),
      url(r'topic-detail/(?P&lt;id&gt;\d+)/(?P&lt;slug&gt;[-\w]+)/$',
          views.topic_detail, name='topic-detail'),
  ]
  </code></pre>
  
  <p><strong>mysite/urls.py</strong></p>
  
  <pre><code>from django.conf.urls import include, url
  from django.contrib import admin
  
  urlpatterns = [
      url(r'^admin/', include(admin.site.urls)),
      url(r'^account/', include('account.urls')),
      url(r'^comments/', include('comments.urls'),
                  namespace='comments'),
  ]
  </code></pre>