Python NumberGuess：控制台卡住了

Question

我已经写了以下代码，当我在提示符下启动程序时，它什么也没发生。为什么？

这是我的代码：

from random import randint
from time import sleep

def get_user_guess() :
  guess = int(input("Guess the dice number: "))
  return guess

def roll_dice(number_of_sides):
  first_roll = randint (1, number_of_sides)
  second_roll = randint (1, number_of_sides)
  max_val = number_of_sides * 2
  print ("The maximum possible value is {:d}" .format(max_val))
  guess = get_user_guess()
  if guess > max_val:
    print ("result is invalid !")
roll_dice(6)