我如何在pygame中碰撞后在其他地方随机产生敌人？

import pygame
import random

# 初始化Pygame
pygame.init()

# 定义屏幕尺寸
screen_width = 800
screen_height = 600
screen = pygame.display.set_mode((screen_width, screen_height))
pygame.display.set_caption("碰撞生成敌人示例")

# 定义颜色
WHITE = (255, 255, 255)
RED = (255, 0, 0)

# 定义玩家类
class Player(pygame.sprite.Sprite):
    def __init__(self):
        super().__init__()
        self.image = pygame.Surface((50, 50))
        self.image.fill(RED)
        self.rect = self.image.get_rect()
        self.rect.center = (screen_width // 2, screen_height // 2)
    
    def update(self):
        # 移动玩家
        keys = pygame.key.get_pressed()
        if keys[pygame.K_LEFT]:
            self.rect.x -= 5
        if keys[pygame.K_RIGHT]:
            self.rect.x += 5
        if keys[pygame.K_UP]:
            self.rect.y -= 5
        if keys[pygame.K_DOWN]:
            self.rect.y += 5

# 定义敌人类
class Enemy(pygame.sprite.Sprite):
    def __init__(self):
        super().__init__()
        self.image = pygame.Surface((30, 30))
        self.image.fill(WHITE)
        self.rect = self.image.get_rect()
        self.rect.x = random.randint(0, screen_width - self.rect.width)
        self.rect.y = random.randint(0, screen_height - self.rect.height)
    
    def update(self):
        # 敌人的更新逻辑
        pass

# 创建精灵组
all_sprites = pygame.sprite.Group()
enemies = pygame.sprite.Group()

# 创建玩家对象
player = Player()
all_sprites.add(player)

# 创建敌人对象
for _ in range(10):
    enemy = Enemy()
    all_sprites.add(enemy)
    enemies.add(enemy)

# 游戏主循环
running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
    
    # 更新玩家和敌人的位置
    all_sprites.update()
    
    # 检测玩家与敌人的碰撞
    if pygame.sprite.spritecollide(player, enemies, True):
        # 如果发生碰撞，重新生成敌人并添加到精灵组中
        enemy = Enemy()
        all_sprites.add(enemy)
        enemies.add(enemy)
    
    # 渲染屏幕
    screen.fill((0, 0, 0))
    all_sprites.draw(screen)
    pygame.display.flip()

# 退出游戏
pygame.quit()