# check if the event is the X button 
        if event.type==pygame.QUIT:
            # if it is quit the game
            pygame.quit() 
            exit(0) 

if event.type == pygame.KEYUP:
            if event.key==pygame.K_w:
                keys[0]=False
            elif event.key==pygame.K_a:
                keys[1]=False
            elif event.key==pygame.K_s:
                keys[2]=False
            elif event.key==pygame.K_d:
                keys[3]=False