问增值税发票识别正常，机票行程单识别失败？

def get_imageVat_text(self):

'''

        增值税发票识别并返回字典格式结果

        '''

        req = models.VatInvoiceOCRRequest()

        req.from_json_string(self.imgget())

        resp = self.client.VatInvoiceOCR(req) 

return json.loads(resp.to_json_string()) # 正常没问题

def get_imageFlight_text(self):

'''

        机票行程单识别并返回字典格式结果

        '''

        req = models.FlightInvoiceOCRRequest()

print(1)

        req.from_json_string(self.imgget())

print(2)

try:

            resp = self.client.FlightInvoiceOCR(req)

except TencentCloudSDKException:

print(resp) # 报错报错：UnboundLocalError: local variable 'resp' referenced before assignment

return json.loads(resp.to_json_string())