def post(self):
    
        if self.has_session_error():
            return
    
    
        payerId = self.request.get('PayerID')
        souvenirInfo = Souvenir.get_souvenir()
        
        
        # もう一度 GetExpressCheckoutで支払額合計を取得する
        paypalResponse = EC.get_express_checkout_details(self.request.get('token'))
        hasGetError = ErrorOperation.has_get_error(self.response, paypalResponse, 'GetExpressCheckoutDetails')
        if hasGetError:
            return
            
        contents = urlparse.parse_qs(paypalResponse.content)
            
        # get時と金額を変えてもエラーも何も出ずに決済されるので、そこが怖い...
        nvpParams = { 'PAYERID': payerId,
                      'PAYMENTREQUEST_0_PAYMENTACTION': 'Sale',
                      'PAYMENTREQUEST_0_AMT': contents['PAYMENTREQUEST_0_AMT'][0],
                      'PAYMENTREQUEST_0_CURRENCYCODE': souvenirInfo['currency'],
                     }
        
        paypalResponse = EC.do_express_checkout_payment(self.request.get('token'),
                                                        nvpParams
                                                       )
        

        hasDoError = ErrorOperation.has_do_error(self.response, paypalResponse, 'DoExpressCheckoutPayment')
        if hasDoError:
            return
        

        self.response.out.write(template.render('html/success.html',{}))