Hi Asad, please have a look at this sample code:
def get_valid_input(): while True: answer = input('Enter a decimal or hexadecimal number: ') if all(character in '0123456789abcdef' for character in answer.lower()): if any(character in 'abcdef' for character in answer.lower()): return answer, 16 return answer, 10 print(f'Please repeat input, only {list(allowed)} are allowed') answer, base = get_valid_input() number = int(answer, base=base) print(number)