title: Django ListView self.kwargs
body: <p>I'm using <strong>Django==1.11</strong>. As I understand from class based views, in this case ListView, you can access url params in <em>get_queryset</em> with <strong>self.kwargs</strong>, as answered <a href="https://stackoverflow.com/a/19361042/6005145">here</a> and <a href="https://stackoverflow.com/a/36950584/6005145">here</a>. And I have no problem when I use <em>get_context_data</em> and self.kwargs. </p>
  
  <p>But I can't get it to work in <em>get_queryset</em>. ¿What I'm doing wrong or missing? I've been trying so many alternatives but I can't get the right one.</p>
  
  <p>My code:</p>
  
  <p><strong>urls</strong></p>
  
  <pre><code>urlpatterns = [
      url(r'^escuelas/(?P&lt;level&gt;(inicial|primario|secundario))/$', SchoolListView.as_view(), name='school-by-level-index'),
      #...
  </code></pre>
  
  <p><strong>view</strong></p>
  
  <pre><code>class SchoolListView(ListView):
      model = School
      template_name = 'edu/adminlte/school_index.html'
  
      def get_queryset(self):
          queryset = super(SchoolListView, self).get_queryset()
  """
  Here below self.kwargs['level'] does not return anything as I would expect
  """
          level = self.kwargs['level']
  
          if level is 'inicial':
              queryset = School.objects.filter(level='I')
              return queryset
          return queryset 
  </code></pre>
  
  <p>Thanks.</p>