Pygame复选框类在本地工作，但在导入时不起作用

import pygame

class Checkbox:
    def __init__(self, x, y, width, height):
        self.rect = pygame.Rect(x, y, width, height)
        self.checked = False

    def draw(self, surface):
        pygame.draw.rect(surface, (255, 255, 255), self.rect, 2)
        if self.checked:
            pygame.draw.line(surface, (255, 255, 255), self.rect.topleft, self.rect.bottomright, 2)
            pygame.draw.line(surface, (255, 255, 255), self.rect.bottomleft, self.rect.topright, 2)

    def handle_event(self, event):
        if event.type == pygame.MOUSEBUTTONDOWN:
            if self.rect.collidepoint(event.pos):
                self.checked = not self.checked

# 在游戏循环中使用Checkbox类
pygame.init()
screen = pygame.display.set_mode((800, 600))
clock = pygame.time.Clock()

checkbox = Checkbox(100, 100, 20, 20)

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        checkbox.handle_event(event)

    screen.fill((0, 0, 0))
    checkbox.draw(screen)
    pygame.display.flip()
    clock.tick(60)

pygame.quit()