问为什么鉴权一直都是失败的？

{'Response': {'Error': {'Code': 'AuthFailure.SignatureFailure', 'Message': 'The provided credentials could not be validated. Please check your signature is correct.'}, 'RequestId': '70bab6f9-0544-4530-93f0-148e009168ea'}}

下面是我简单的测试代码，一直都是失败

import time

import base64

import hmac

from hashlib import sha1

from urllib.parse import quote

import requests

SecretId = "AKIDmRuAD7yE2neQ2SSfS5VkneLn33nRse3F"

SecretKey = "********"

send_data = {'Action' : 'DescribeInstances',

'InstanceIds.0' : 'ins-ni190jc6',

'Limit' : 20,

'Nonce' : 11886,

'Offset' : 0,

'Region' : 'ap-hongkong',

'SecretId' : SecretId,

'Timestamp' : int(time.time()),

'Version': '2017-03-12'}

def signature():

sort_send_data = dict(sorted(zip(send_data.keys(), send_data.values())))

srcStr = 'GETcvm.tencentcloudapi.com/?' + '&'.join([k + '=' + str(v) for k, v in sort_send_data.items()])

hmac_str = hmac.new(SecretKey.encode("utf-8"), srcStr.encode("utf-8"), sha1).digest()

sign_str = base64.b64encode(hmac_str).decode("utf-8")

sign_str_splice = quote(sign_str, safe='')

sort_send_data["Signature"] = sign_str_splice

post_data = dict(sorted(zip(sort_send_data.keys(), sort_send_data.values())))

return post_data

if __name__ == '__main__':

url = "https://cvm.tencentcloudapi.com"

post_data = signature()

print(post_data)

resp = requests.get(url, params=post_data)

print(resp.json())

print(resp.url)