Ucloud api signature 生成 (python3)

import hashlib

def _verfy_ac(private_key, params):
items = sorted(params.items(), key=lambda x: x[0])
params_data = ""
for i in items:
params_data = params_data + i[0] + i[1]
params_data = params_data + private_key

sign = hashlib.sha1()
sign.update(params_data.encode("utf8"))
signature = sign.hexdigest()

return signature

s = _verfy_ac("私钥", {
"Action": "DescribeImage",
"PublicKey": "公钥",
"OsType": "Linux",
"Region": "cn-bj2"
})

print(s)