我怎样才能改变我的pygame棋盘从鼠标位置移动到按键？

import pygame
import sys

# 初始化pygame
pygame.init()

# 定义棋盘对象
class Chessboard:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def draw(self, screen):
        pygame.draw.rect(screen, (255, 255, 255), (self.x, self.y, 100, 100))

# 创建屏幕对象
screen = pygame.display.set_mode((800, 600))

# 创建棋盘对象
chessboard = Chessboard(0, 0)

# 游戏主循环
while True:
    # 处理事件
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        elif event.type == pygame.MOUSEMOTION:
            # 鼠标移动事件
            mouse_x, mouse_y = event.pos
            chessboard.x = mouse_x
            chessboard.y = mouse_y
        elif event.type == pygame.KEYDOWN:
            # 键盘按下事件
            if event.key == pygame.K_LEFT:
                chessboard.x -= 10
            elif event.key == pygame.K_RIGHT:
                chessboard.x += 10
            elif event.key == pygame.K_UP:
                chessboard.y -= 10
            elif event.key == pygame.K_DOWN:
                chessboard.y += 10

    # 绘制棋盘
    screen.fill((0, 0, 0))
    chessboard.draw(screen)

    # 更新屏幕
    pygame.display.flip()