Python黑杰克游戏随机出现IndexError: list index out of range问题求助

我是Python新手，正在开发黑杰克游戏作为结业项目。代码多数时候运行正常，但会随机崩溃，触发IndexError: list index out of range错误，该错误有时在初始化阶段出现，有时在循环过程中触发。我理解该错误含义，但无法定位代码中索引越界的原因。

报错栈信息 #

Traceback (most recent call last):
File "C:\Users\carlo\Documents\training\confusion_list_call.py", line 49, in
initial_card()
File "C:\Users\carlo\Documents\training\confusion_list_call.py", line 24, in initial_card
computer_card.append(cards[random.randint(0,len(cards))])
IndexError: list index out of range

代码实现 #

import random

cards = [11, 2, 3, 4, 5, 6, 7, 8, 9, 10, 10, 10, 10]

computer_card = []
user_card = []
computer_total = 0 
user_total = 0


def computer_deal():
    global computer_card
    computer_card.append(cards[random.randint(0,len(cards))])

def user_deal():
    global user_card
    user_card.append(cards[random.randint(0,len(cards))])

def initial_card(): 
  for _initial in range(1, 3): 
        global user_card 
        global computer_card 
        user_card.append(cards[random.randint(0,len(cards))]) ##randomly happens here or next line
        computer_card.append(cards[random.randint(0,len(cards))]) 

def sum_cards(): 
  global computer_total 
  global user_total
  user_total = 0
  computer_total = 0
  for total_c in computer_card:
    computer_total += total_c 
  for total_u in user_card:
    user_total += total_u

def reset_game():
  global computer_total 
  global user_total 
  global computer_card 
  global user_card 
  computer_total = 0
  user_total = 0
  computer_card.clear()
  user_card.clear()
  

continue_game = True
while continue_game:  
  initial_card() 
  print(f"Your cards: {user_card} \nComputer's Card {computer_card[0]}") 
  choice = input("Would you like another card 'y' or 'n' \n ") 
  
  no_bust = True 
  if choice == 'y':
    
    while no_bust:
      user_deal()
      sum_cards()
      print(f"Users new deck is: {user_card}") 
      print(f"Computer's total: {computer_total} and your total: {user_total}\n ")
      
      if user_total > 21: 
        print("You loss!")
        no_bust = False 
      elif computer_total == user_total:
        print("push: tied! ")
        no_bust = False
      else: 
        choice = input("Would you like another card 'n' or 'y'")
        if choice == 'y': 
          no_bust = True
        if choice == 'n': 
          if computer_total == user_total:
            print("push: tied! ")
          no_bust = False
  

  if choice == 'n': 
    if computer_total >= 17 and computer_total < 21: 
      if computer_total > user_total: 
        print(f"You loss!, Computer's total: {computer_total} and your total: {user_total}")
      else:
        print(f"You Win!, Computer's total: {computer_total} and your total: {user_total}")
  
    under_17 = True
    while under_17: 
      if computer_total < 17: 
        computer_deal() 
        sum_cards() 
        print(f"test3: computers new deck ~~~ > {computer_card}\nTest4: computers new total ~~~~ > {computer_total}")
        if computer_total == user_total:
          print("Game is tied: push")
          under_17 = False
        elif computer_total > 21:
          print("Computer has bust, You won!")
          under_17 = False
        elif computer_total >= 17 and computer_total <= 21:
          if computer_total > user_total:
            print(f"test5: Computer's total: {computer_total} and your total: {user_total}")
            print("You lose!")
            under_17 = False
          if computer_total < user_total:
            print("You win!")
            under_17 = False
        else:
          under_17 = True
  
  continue_choice = input("Would you like to play another game, 'y' or 'n'")
  if continue_choice == 'n':
    print("Thank you for playing Black Jack, have a good day!")
    continue_game = False
  if continue_choice == 'y':
    reset_game()
    continue_game is True

我知道代码结构较混乱，因为还没学习类的使用。我曾移除initial_card()的函数参数，也将缩进从制表符改为空格，但问题仍未解决。

内容的提问来源于stack exchange，提问作者Carlos Colón