按照官方提供的python解密小程序unionid demo 报错 'utf-8' codec can't decode byte 0xba in position 1 :invalid start byte 尝试了将解密结果decode ,同样报错 尝试了各种编码方式，gbk,iso等都报错 def decrypt(self, encryptedData, iv):         try:             sessionKey = base64.b64decode(self.sessionKey)             encryptedData = base64.b64decode(encryptedData)             iv = base64.b64decode(iv)             cipher = AES.new(sessionKey, AES.MODE_CBC, iv)             decrypted = json.loads(self._unpad(cipher.decrypt(encryptedData)))             if decrypted['watermark']['appid'] != self.appId:                 raise Exception('Invalid Buffer')             return decrypted         except Exception as err:             print(str(err))              def _unpad(self, s):         return s[:-ord(s[len(s)-1:])]