code: def transaction(self, request):
          
          request_url = request.build_absolute_uri()
          parsed_url = urlparse.urlparse(request_url)
          query = parsed_url.query
          dd = dict(map(lambda x: x.split("="), query.split("&")))
          resp = self.purchase(100, dd)
          return HttpResponseRedirect("%s?status=%s" %(reverse("app_offsite_amazon_fps"),
                                  resp["status"]))
docs: Ideally at this method, you will check the 
          caller reference against a user id or uniquely
          identifiable attribute (if you are already not 
          using it as the caller reference) and the type 
          of transaction (either pay, reserve etc). For
          the sake of the example, we assume all the users
          get charged $100