在ecdsa，python中的正确编码

from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives.serialization import Encoding, PublicFormat

# 生成ECDSA密钥对
private_key = ec.generate_private_key(ec.SECP256K1())
public_key = private_key.public_key()

# 对待签名的数据进行哈希
data = b"Hello, world!"
digest = hashes.Hash(hashes.SHA256())
digest.update(data)
hash_value = digest.finalize()

# 使用私钥对哈希值进行签名
signature = private_key.sign(hash_value, ec.ECDSA(hashes.SHA256()))

# 使用公钥对签名进行验证
try:
    public_key.verify(signature, hash_value, ec.ECDSA(hashes.SHA256()))
    print("Signature is valid.")
except InvalidSignature:
    print("Signature is invalid.")