如何确定Tic Tac Toe中的获胜者

def check_winner(board):
    # 检查行
    for row in board:
        if row[0] == row[1] == row[2] != ' ':
            return row[0]
    
    # 检查列
    for col in range(3):
        if board[0][col] == board[1][col] == board[2][col] != ' ':
            return board[0][col]
    
    # 检查对角线
    if board[0][0] == board[1][1] == board[2][2] != ' ':
        return board[0][0]
    if board[0][2] == board[1][1] == board[2][0] != ' ':
        return board[0][2]
    
    # 平局
    return '平局'

# 示例游戏棋盘
board = [['X', 'O', 'X'],
         ['O', 'X', 'O'],
         ['O', 'X', 'O']]

winner = check_winner(board)
print("获胜者:", winner)