def win_check(board, mark):

    if board[0] = board[3] = board[6] = mark:

        return True

    elif board[1] = board[4] = board[7] = mark:

        return True

    elif board[2] = board[5] = board[8] = mark:

        return True

    elif board[0] = board[4] = board[8] = mark:

        return True

    elif board[2] = board[4] = board[6] = mark:

        return True

    else:

        return False

    pass


빡통이라서 왜 안되는지 모르겟음