Ошибка в файле примера API Python в ACR

Question

Я пытаюсь запустить пример файла API ACR.

https://github.com/acrcloud/webapi_example/blob/master/identify%20protocol%201%20(recommended)/IdentifyProtocolV1_1.py

This is a demo program which implements ACRCloud Identify Protocol V1 with the third party library "requests".
We recomment you implement your own app with "requests" too.
You can install this python library by:
1) sudo easy_install requests 
2) sudo pip install requests

import sys
import os
import base64
import hmac
import hashlib
import time
import requests  

'''
Replace "###...###" below with your project's host, access_key and access_secret.
'''
access_key = "###YOUR_ACCESS_KEY###"
access_secret = "###YOUR_ACCESS_SECRET###"
requrl = "http://###YOUR_HOST###/v1/identify"


http_method = "POST"
http_uri = "/v1/identify"
data_type = "audio"
signature_version = "1"
timestamp = time.time()

string_to_sign =    http_method+"\n"+http_uri+"\n"+access_key+"\n"+data_type+"\n"+signature_version+"\n"+str(timestamp)

sign = base64.b64encode(hmac.new(access_secret, string_to_sign,   digestmod=hashlib.sha1).digest())

f = open(sys.argv[1], "rb")
sample_bytes = os.path.getsize(sys.argv[1])

files = {'sample':f}
data = {'access_key':access_key,
    'sample_bytes':sample_bytes,
    'timestamp':str(timestamp),
    'signature':sign,
    'data_type':data_type,
    "signature_version":signature_version}

r = requests.post(requrl, files=files, data=data)
r.encoding = "utf-8"
print r.text

Но я получил ошибку в коде sign = base64.b64encode(hmac.new(access_secret, string_to_sign, digestmod=hashlib.sha1).digest()) и ошибка заключается в том, что "отображение символов должно возвращать целое число, None или Unicode". Мне действительно нужна твоя помощь.