python搖骰子猜大小的小游戲

#小游戲，搖篩子押大小的小游戲
玩家初始有1000塊錢，可以壓大壓小作為賭注
import random
#定義搖篩子的函數：
def roll_dice(number = 3,points = None):
    print ('<<<<< Roll The Dice >>>>>')
    if points is None:
        points = []
    while number > 0:
        point = random.randrange(1,7)
        points.append(point)
        number = number - 1
    return points

#將點數轉換為大小的函數：
def roll_result(total):
    isBig = 11 <= total < 18
    isSmall = 3 <= total < 10
    if isBig:
        return 'isBig'
    elif isSmall:
        return 'isSmall'

#開始游戲的函數;

def start_game():
    you_money = 1000
    while you_money > 0:
        print ('<<<<< GAME START >>>>>')
        choices = ['isBig','isSmall']
        your_choices = input('isBig or isSmall:')
        if your_choices in choices:
            you_bet = int(input('How nuch you wana bet? :'))
            points = roll_dice()
            total = sum(points)
            youWin = your_choices == roll_result(total)
            if youWin:
                you_money = you_money + you_bet
                print('The points are', points, 'You win !')
                print('You gained {},you have {} now'.format((you_bet,you_money)))
            else:
                you_money = you_money - you_bet
                print('The points are', points, 'You lose !')
                print('You lost {},you have {} now'.format(you_bet,you_money))
        else:
            print('Invalid Words')
    else:
        print ('GAME IS OVER!')
start_game()