code: def ask_int(question: str, default: int = None) -> int:
      
      default_q = " [default: {0}]: ".format(
          default) if default is not None else ""
      answer = input("{0} [{1}]: ".format(question, default_q))
  
      if not answer:
          if default is None:
              print("No default set, try again.")
              return ask_int(question, default)
          return default
  
      if any(x not in "1234567890" for x in answer):
          print("Please enter only numbers (0-9).")
          return ask_int(question, default)
  
      return int(answer)
docs: Asks for a number in a question