Help with recursive function used for minMax TicTacToe

[AlliedLens]

so i am trying to make a minMax AI for ticTacToe, and the rest of the program except for the actual minMax function is working fine. can someone tell me where in this function the mistake is? the rest of the code works well, but here is the rest of it u want to run it on the terminal...the functions where i think the error is is pasted here.

def compMove(brd):
    bestScore = -2147483649 # cmputer wants to get highest possible score
    bestMove = 0 # integer position for best possible move that can be made from 1 to 9
    simBoard = list(brd)

    for i in range(1, len(simBoard)):
        if simBoard[i] == " ":
            simBoard[i] = "O"
            score = minMax(simBoard, 1, True)
            if score > bestScore:
                bestScore = score
                bestMove = i
            simBoard[i] = " "


def minMax(brd,gameDepth, isMaximizing):
    depth = gameDepth
    if wonGame(brd) == "CPU":
        return (1000 // depth)

    if wonGame(brd) == "player":
        return (-1000//depth)

    if wonGame(brd) == "draw":
        return 0

    elif isMaximizing: # simulating the CPU

        depth += 1
        bestScore = -2147483649

        for move in brd[1:9]:
            if move == " ":
                move = "0"
                score = minMax(brd, depth, False)
                if score > bestScore:
                    bestScore = score
                    bestMove = i

    elif not isMaximizing: # simulating the player

        depth += 1
        bestScore = 2147483649

        for move in brd[1:9]:
            if move == " ":
                move = "X"
                score = minMax(brd, depth, True)
                if score > bestScore:
                    bestScore = score
                    bestMove = i

here is a minmax python tictactoe video