title: I have an error on django athentication system with authenticate () method
body: <p>I have an issue with autenticate () method , please help me.
  it return to me '' the view didn't return an httpresponse . It returned none instead.</p>
  <pre><code>def registrazione (request):
      if request.method == 'POST':
          form = FormSito(request.POST)
          if form.is_valid():
              username = form.cleaned_data [&quot;username&quot;]
              password = form.cleaned_data [&quot;password&quot;]
              User.objects.create_user (
                  username = 'username',
                  password = 'password'
              )
              
              user = authenticate (request,User)
          else: 
              form = FormSito()
              context = { form : 'form' }
              return render (request,&quot;registration/form/registrazione.html&quot;, context)
  </code></pre>