实现交易签名验证HMAC-SHA256防篡改

def solve():
    from pyodide.http import open_url
    account_types_csv = open_url(____).read()
    payment_channels_csv = open_url(____).read()
    transaction_limits_csv = open_url(____).read()
    accounts_csv = open_url(____).read()
    transfers_csv = open_url(____).read()
    fraud_rules_csv = open_url(____).read()
    audit_logs_csv = open_url(____).read()
    import hmac, hashlib
    secret = b'____'
    msg = '____'
    sig = hmac.new(secret, msg.encode(), hashlib.sha256).hexdigest()
    print(____)
    print(____)
    tampered = '____'
    sig2 = hmac.new(secret, tampered.encode(), hashlib.sha256).hexdigest()
    result = '____' if sig == sig2 else '____'
    print(____)