code: def callback(self, request, **kwargs):
          
          access_token = request.session['oauth_token'] + "#TH#"
          access_token += str(request.session['oauth_id'])
          kwargs = {'access_token': access_token}
          return super(ServiceGithub, self).callback(request, **kwargs)
docs: Called from the Service when the user accept to activate it
              :param request: request object
              :return: callback url
              :rtype: string , path to the template