code: def callback(self, request, **kwargs):
          
          code = request.GET.get('code', '')
          redirect_uri = '%s://%s%s' % (request.scheme, request.get_host(), reverse("reddit_callback"))
          reddit = RedditApi(client_id=self.consumer_key,
                             client_secret=self.consumer_secret,
                             redirect_uri=redirect_uri,
                             user_agent=self.user_agent)
          token = reddit.auth.authorize(code)
  
          UserService.objects.filter(user=request.user, name='ServiceReddit').update(token=token)
          return 'reddit/callback.html'
docs: Called from the Service when the user accept to activate it
              the url to go back after the external service call
              :param request: contains the current session
              :param kwargs: keyword args
              :type request: dict
              :type kwargs: dict
              :rtype: string