我正在学习Python，尽管我已经找到了关于这个错误的资源，但当应用到我的案例中时，他们的解决方案并不是特别清楚。
这就是：
完整错误：

Traceback (most recent call last):
  File "main.py", line 136, in <module>
    game()
  File "main.py", line 131, in game
    dealer_result = dealer()
  File "main.py", line 66, in dealer
    dvalue = value(dealer_hand)
  File "main.py", line 36, in value
    value += cards.get(c)
TypeError: unsupported operand type(s) for +=: 'int' and 'NoneType'

背景：

• 这是21点游戏。
• game（）是一个围绕整个游戏的函数，每个方面都有一个完整的函数子集。
• 错误不一致

代码流：我有卡片2到A，它们的值在字典中定义。

cards = {
      "2": 2,
      "3": 3,
      "4": 4,
      "5": 5,
      "6": 6,
      "7": 7,
      "8": 8,
      "9": 9,
      "10": 10,
      "J": 10,
      "Q": 10,
      "K": 10,
      "A": 11,
  }

游戏从定义玩家和庄家手牌的变量开始
player_hand = start()和dealer_hand = start()
其中

def start():
      hand = []
      hand.extend([random.choice(list(cards)), random.choice(list(cards))])
      return hand

全局“flag”变量被预先设置为“h”以允许代码进入游戏的主要部分上的循环
首先，我们将使用value(hand)函数计算玩家手牌的值：

def value(hand):
      value = 0
      for c in hand:
          if c != "A":
              value += cards.get(c)
          elif c == "A" and value >= 11:
              value += 1
          else:
              value += 11
      return value

并将其归因于p_value变量。
我想这就是错误的地方，虽然，由于手是从字典中随机选择的卡片，它怎么可能在浏览同一本字典时找不到这样的卡片呢？
玩家阶段：

def main(flag):
      p_value = value(player_hand)
      if p_value == 21:
          result = "blackjack"
      else:
          while flag == "h":
              if p_value == 21:
                  flag = "s"
              elif p_value > 21:
                  print("Bust")
                  flag = "s"
              if flag != "s":
                  flag = str(input("[h]it, [s]tay or [q]uit?: "))
              if flag == "h":
                  player_hand.extend(hit())
                  p_value = value(player_hand)
                  print("Player: Current value: " + str(p_value) + ". Current hand: " + ', '.join(player_hand))
              elif flag == "q":
                  exit()
      result = p_value
      return result

然后，我使用返回的结果来比较最终玩家结果与最终庄家结果
经销商阶段：

def dealer():
      dvalue = value(dealer_hand)
      print("Dealer value: " + str(dvalue) + ". Dealer hand: " + ', '.join(dealer_hand))
      if dvalue == 21:
          result = "blackjack"
      else:
          while dvalue < 17:
              dealer_hand.extend(hit())
              dvalue = value(dealer_hand)
              print("Dealer value: " + str(dvalue) + ". Dealer hand: " + ', '.join(dealer_hand))
          result = dvalue
      return result

发生错误的真实的场景：

Play again? y/n: y
Player: Current value: 10. Current hand: 2, 8
Dealer: Current hand: ?, 5
[h]it, [s]tay or [q]uit?: s
Dealer value: 7. Dealer hand: 2, 5
Traceback (most recent call last):
  File "main.py", line 136, in <module>
    game()
  File "main.py", line 131, in game
    dealer_result = dealer()
  File "main.py", line 66, in dealer
    dvalue = value(dealer_hand)
  File "main.py", line 36, in value
    value += cards.get(c)
TypeError: unsupported operand type(s) for +=: 'int' and 'NoneType'

预期结果是庄家继续循环hit（）函数，直到他的手牌值value(dealer_hand)等于或大于17。