为什么我会得到：回溯（最近的一次电话）？此外，TypeError:“NoneType”对象不是subscriptab

Question

我希望这里的人能帮我做这些，我正在尝试用minimax做一个tic-tac-toe游戏。你知道吗

Traceback (most recent call last):
  File "C:\Users\Abdul\Desktop\A.I\finishingAttempt1.2.py", line 92, in <module>
    max_move=Minimax(state)
  File "C:\Users\Abdul\Desktop\A.I\finishingAttempt1.2.py", line 69, in Minimax
    minimum=act[0]
TypeError: 'NoneType' object is not subscriptable

对于回溯，我试图保存该变量中返回的值。第二个，我试图保存变量中的第一个元素。这是我的密码：

def player(state):#deciding turn
    x_count=0
    o_count=0
    for i in state[board]:
        for j in state[board]:
            if state[board][i,j]=='x':
                x_count+=1
            elif state[board][i,j]=='o':
                o_count+=1
            if x_count>o_count:
                player='o'
            elif o_count>x_count:
                player='x'              
    return player
def successors(state):#returns possible successors for given baord
    #removed and replaced actions(s)function
    b=[]
    if not isWin(state['player'],state['board']):
        for i in range(9):
            if state['board'][i]=='-':
                nb=[n for n in state['board']]
                nb[i]=state['player']
                b.append("".join(nb))
        return b
    return terminal(state)
def result(state,action):
    #called from Minimax() 
    state['board']=action 
    return state

def terminal(state):#checks for winning scenarios, returns isWIn(s,board), where s is the player
    for i in board:
        if board[0]==board[1]and board[1]==board[2]:
            return isWin(player,board)
        if board[3]==board[4]and board[4]==board[5]:
            return isWin(player,board)
        if board[6]==board[7]and board[7]==board[8]:
            return isWin(player,board)
        if board[2]==board[4]and board[4]==board[6]:
            return isWin(player,board)
        if board[0]==board[4]and board[4]==board[8]:
            return isWin(player,board)

    return False
def utility(state):
    #the VALUE for minmax(1,-1,0), haven't worked it in to update 'utility' value in state
    if terminal(state):
        if state['player']=='x':
            return 1
        elif state['palyer']=='o':
            return -1
    return 0

def Minimax(state):#calls successors(state)for each player and puts list b in its dunction and then uses result(state,action)
    if state['terminal']:
        return state['utility']
    elif state['player']=='o':
        #successors(state)#action for max
        act=successors(state)
        maximum=act[0]
        for a in act:
            tmp=Minimax(result(state,act))
            if tmp>maximum:
                maximum=tmp                
        return maximum
    elif state['player']=='x':
        act=successors(state)
        minimum=[]
        minimum[0]=act[0]
        for a in act:
            tmp=minimum(result(state,act))
            if tmp<minimum:#changed comparison for Min
                minimum=tmp                
        return minimum
def isWin(s,board):#called for terminal states as boolean
    if s=='x':
        return True
    if s=='o':
        return False


'''--------------------------------now for running main------------------------'''

board = ['-']*9
min_move=int(input("choose a spot: "))
board[min_move]='x'
print (board)
print ('please wait, while I think..')
state={'player':'x','utility':0,'terminal':False,'board':board}
#while (state['utility']!=1 or state['utility']!=0):
while (state['terminal']==False):
                         max_move=Minimax(state)
                         state['player']= player(state)
                         if terminal!=True:
                             print('you lose, game over')
                         else:
                             if (board[max_move]!='x' and board[max_move]!='o'):
                                 board[max_move]='o'
                         state['player']=player(state)
                         if (board[min_move]!='x' and board[min_move]!='o'):
                             board[min_move]='x'
                         print (board)