serialize function
Implementation
String serialize(String hex) {
/// Here the hexadecimal value is first checked if it has 8 digits, if not a 0 is added in front and then rotated.
String newHex = isNotEven(hex);
List list = [
for (int a = hex.length; a > 0; a -= 2) newHex.substring(a - 2, a)
];
String hexTurn = list.join();
return hexTurn;
}