Проверка наличия значения в массиве

Я пишу code для игры в крестики-нолики и пытаюсь найти способ проверить, заполнена ли позиция, прежде чем сделать нужный ход. Решение, которое я вывел и которое пришло мне в голову наиболее естественно, состояло в том, чтобы инициализировать пустой список, для первого хода сделать его пустым, а для всех последующих ходов сверить со списком, если ход есть в списке, не делать его, иначе сделать.

полный code, если нужно:

class Tictactoe:

def __init__(self,playerone,playertwo):
    self.playerone = playerone
    self.playertwo = playertwo
    self.made_moves = []

def makeMove(self):

    marker = "O"
    
    xcoor,ycoor = self.getMove()

    
    

    #if first move, make the move
    if len(self.made_moves)== 0:
        self.board[xcoor][ycoor] = marker
        self.made_moves += (xcoor,ycoor)
    
    #for all other moves, check to see if the position is filled
    else:
        if [xcoor,ycoor] in self.made_moves:
            print(f"The position at {xcoor,ycoor} is already full, please try again.")
        else:
            self.board[xcoor][ycoor] = marker
            self.made_moves += xcoor,ycoor

    return
        

class Tictactoe:

def __init__(self,playerone,playertwo):
    self.playerone = playerone
    self.playertwo = playertwo
    self.made_moves = []
    
    
    
    

def newBoard(self):
    # creates new board
    self.board = [[None, None, None],
             [None, None, None],
             [None, None, None]
             ]
    
    return

def renderBoard(self):
    # Prints current state of the board
    for row in self.board:
        print("|", end="")
        for cell in row:
            if cell is None:
                print("   |", end="")
            else:
                print(f" {cell} |", end="")
        print("\n" + "-" * 13)

    return


def getMove(self):
    print("Coordinates must range from 0 to 2, 0 corresponding to the first row/column, 
    onwards")
    xcoor = int(input("What is your x coordinate?"))
    ycoor = int(input("What is your y coordinate?"))
    
    if xcoor not in {0,1,2} or ycoor not in {0,1,2}:
        print("Coordinates must be between 0 and 2")

    
    return xcoor,ycoor


def makeMove(self):

    marker = "O"
    
    xcoor,ycoor = self.getMove()

    
    

    #if first move, make the move
    if len(self.made_moves)== 0:
        self.board[xcoor][ycoor] = marker
        self.made_moves += (xcoor,ycoor)
    
    #for all other moves, check to see if the position is filled
    else:
        if [xcoor,ycoor] in self.made_moves:
            print(f"The position at {xcoor,ycoor} is already full, please try again.")
        else:
            self.board[xcoor][ycoor] = marker
            self.made_moves += xcoor,ycoor

    return
        




def getWinner(self):
    #todo write win conditions
    '''if player one marks 3 in a row, player one wins, end game
    if player two marks 3 in a row, player 2 wins, end game
    '''
    pass

def resetButton(self):
    #todo: create a reset button that clears the board.
    pass

def runGame(self):
        test = Tictactoe("playerone", "playertwo")
        print(test.newBoard())
        for i in range(9):
            print(test.makeMove())
            print(test.renderBoard())
        print("Game Over, it is a draw")


def isBoardFull(self):
    #todo: write code that checks if board is full
    pass


def main():
    test = Tictactoe("playerone", "playertwo",)
    print(test.runGame())

if __name__ == '__main__':
    main()