AOL database files: address book (.aby)

def is_aby(file_path: str) -> bool:
    """Check if file is a valid ABY by magic bytes."""
    signature = bytes([0x41, 0x4F, 0x4C, 0x44, 0x42])
    with open(file_path, "rb") as f:
        return f.read(5) == signature

function isABY(buffer: Buffer): boolean {
  const signature = Buffer.from([0x41, 0x4F, 0x4C, 0x44, 0x42]);
  return buffer.subarray(0, 5).equals(signature);
}

func IsABY(data []byte) bool {
    signature := []byte{0x41, 0x4F, 0x4C, 0x44, 0x42}
    if len(data) < 5 {
        return false
    }
    return bytes.Equal(data[:5], signature)
}