def play():
    'Play a game of naughts and crosses against the computer.'
    ai = {'X': player_move, 'O': random_move}
    board = Board()
    while not board.winner:
        x, y = ai[board.player](board)
        board = board.make_move(x, y)
    print(board, end='\n\n')
    print(board.winner)