code: def email_confirm(request, confirmation_key,
                    template_name='userena/email_confirm_fail.html',
                    success_url=None, extra_context=None):
      
      user = UserenaSignup.objects.confirm_email(confirmation_key)
      if user:
          if userena_settings.USERENA_USE_MESSAGES:
              messages.success(request, _('Your email address has been changed.'),
                               fail_silently=True)
  
          if success_url: redirect_to = success_url
          else: redirect_to = reverse('userena_email_confirm_complete',
                                      kwargs={'username': user.username})
          return redirect(redirect_to)
      else:
          if not extra_context: extra_context = dict()
          return ExtraContextTemplateView.as_view(template_name=template_name,
                                              extra_context=extra_context)(request)
docs: Confirms an email address with a confirmation key.
  
      Confirms a new email address by running :func:`User.objects.confirm_email`
      method. If the method returns an :class:`User` the user will have his new
      e-mail address set and redirected to ``success_url``. If no ``User`` is
      returned the user will be represented with a fail message from
      ``template_name``.
  
      :param confirmation_key:
          String with a SHA1 representing the confirmation key used to verify a
          new email address.
  
      :param template_name:
          String containing the template name which should be rendered when
          confirmation fails. When confirmation is successful, no template is
          needed because the user will be redirected to ``success_url``.
  
      :param success_url:
          String containing the URL which is redirected to after a successful
          confirmation.  Supplied argument must be able to be rendered by
          ``reverse`` function.
  
      :param extra_context:
          Dictionary of variables that are passed on to the template supplied by
          ``template_name``.