如何在pygame中移动一个表面

import pygame
import sys

pygame.init()

screen = pygame.display.set_mode((800, 600))

surface = pygame.Surface((50, 50))

surface.fill((255, 0, 0))

surface_rect = surface.get_rect()
surface_rect.center = (400, 300)

clock = pygame.time.Clock()

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    # 移动表面
    keys = pygame.key.get_pressed()
    if keys[pygame.K_LEFT]:
        surface_rect.move_ip(-5, 0)
    if keys[pygame.K_RIGHT]:
        surface_rect.move_ip(5, 0)
    if keys[pygame.K_UP]:
        surface_rect.move_ip(0, -5)
    if keys[pygame.K_DOWN]:
        surface_rect.move_ip(0, 5)

    # 清空屏幕
    screen.fill((0, 0, 0))

    # 在窗口上绘制表面
    screen.blit(surface, surface_rect)

    # 更新屏幕显示
    pygame.display.flip()

    # 控制帧率
    clock.tick(60)