Почему когда y = yApple Яблоко свою позицию не меняет (y это вертикальная позиция змеи, а yApple вы сами понимаете)

    import pygame
    from random import randint
    
    pygame.init()
    
    x = 300
    y = 200
    
    xChange = 0
    yChange = 0
    
    WIDTH  = 1200
    HEIGHT = 800
    
    keys = pygame.key.get_pressed()
        
    sc = pygame.display.set_mode((WIDTH,HEIGHT))
    FPS = 60
    clock = pygame.time.Clock()
    game = True
#змейка    
    class snake():
        def head(screen, color, posX, posY,  width, height):
#яблоко             pygame.draw.rect(screen, color, [posX, posY, width, height])    
    class apple():
        def init():
            xApple = 600
            yApple = 400
            pygame.draw.rect(sc, (255,0,0), [xApple, yApple, 20, 20])
            if y == yApple:
                xApple = randint(1,1199)
                yApple = randint(1,799)
    
                
#основной цикл    
    while game:
    
        sc.fill((0,0,0))
    
        apple.init()    
        snake.head(sc, (0,255,0), x, y, 20, 20)
    
        for i in pygame.event.get():
            if i.type == pygame.QUIT:
                game = False
        keys = pygame.key.get_pressed()     
#движение    
        if keys[pygame.K_RIGHT]:
            xChange = 1
            yChange = 0
        elif keys[pygame.K_LEFT]:
            xChange = -1
            yChange = 0
        elif keys[pygame.K_UP]:
            yChange = -1
            xChange = 0
        elif keys[pygame.K_DOWN]:
            yChange = 1
            xChange = 0 
                    
        x += xChange
        y += yChange
    
        pygame.display.update()
        clock.tick(120)