如何验证Python中的RSA SHA1签名？

from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import padding
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.serialization import load_pem_private_key, load_pem_public_key
from cryptography.hazmat.backends import default_backend

# 私钥签名
private_key = load_pem_private_key(
    data=private_pem,
    password=None,
    backend=default_backend()
)

# 使用私钥对消息进行签名
signature = private_key.sign(
    message,
    padding.PSS(
        mgf=padding.MGF1(hashes.SHA1()),
        salt_length=padding.PSS.MAX_LENGTH
    ),
    hashes.SHA1()
)

# 公钥验证签名
public_key = load_pem_public_key(
    data=public_pem,
    backend=default_backend()
)

# 使用公钥验证签名
try:
    public_key.verify(
        signature,
        message,
        padding.PSS(
            mgf=padding.MGF1(hashes.SHA1()),
            salt_length=padding.PSS.MAX_LENGTH
        ),
        hashes.SHA1()
    )
    print("签名验证成功")
except InvalidSignature:
    print("签名验证失败")