python obf Crâck me

import base64
import re


BANNER = "=" * 70
HEADER = "dr" + "x" * 59
VALID_USERNAME = "admin"
VALID_PASSWORD = "admin"
FLAG = "FLAG{Y0U_CR4CK3D_TH3_0BFU5C4T10N_M45T3R}"
LICENSE_RE = re.compile(r"^[A-Z0-9]{4}(?:-[A-Z0-9]{4}){3}$")


def print_banner() -> None:
    print(BANNER)
    print(f"  {HEADER}")
    print(BANNER)
    print()


def authenticate(username: str, password: str) -> bool:
    return username == VALID_USERNAME and password == VALID_PASSWORD


def decode_license(encoded: str) -> str | None:
    try:
        decoded = base64.b64decode(encoded).decode("ascii")
    except Exception:
        return None
    return decoded


def validate_license(encoded: str) -> bool:
    decoded = decode_license(encoded)
    if decoded is None:
        return False
    if not LICENSE_RE.fullmatch(decoded):
        return False
    return sum(map(ord, decoded)) == 1337


def main() -> int:
    print_banner()
    print("[*] Authentication Required")
    print()
    username = input("Username: ")
    password = input("Password: ")
    print()
    print("[*] Verifying credentials...")

    if not authenticate(username, password):
        print("[-] Authentication failed!")
        print("[!] Hint: Try common default credentials")
        return 1

    print("[+] Authentication successful!")
    print(f"[+] Welcome, {username}!")
    print()
    print("[*] License Validation Required")
    print()
    license_key = input("Enter License Key (Base64): ")
    print()
    print("[*] Validating license...")

    if not validate_license(license_key):
        print("[-] Invalid license key!")
        print("[!] Hint: Format must be XXXX-YYYY-ZZZZ-WWWW with checksum 1337")
        return 1

    print("[+] License validated successfully!")
    print()
    print(BANNER)
    print("[+] ACCESS GRANTED")
    print(BANNER)
    print()
    print(f"[+] Your flag: {FLAG}")
    print()
    print("[+] Congratulations! You successfully reversed the obfuscation!")
    print()
    return 0


if __name__ == "__main__":
    raise SystemExit(main())