def check_events(ai_settings, screen, ship):
    for event in pygame.event.get():
        if event.type==pygame.QUIT:
                sys.exit()
        elif event.type==pygame.KEYDOWN:
            check_keydown_events(event, ship)
        elif event.type==pygame.KEYUP:
            check_keyup_events(event, ship)
def check_keydown_events(event, ship):
    if event.key==pygame.K_RIGHT:
        ship.moving_right=True
    elif event.key==pygame.K_LEFT:
        ship.moving_left=True
    elif event.key==pygame.K_UP:
        ship.moving_up=True
    elif event.key==pygame.K_DOWN:
        ship.moving_down=True
def check_keyup_events(event, ship):
    if event.key==pygame.K_RIGHT:
        ship.moving_right=False
    elif event.key==pygame.K_LEFT:
        ship.moving_left=False
    elif event.key==pygame.K_UP:
        ship.moving_up=False
    elif event.key==pygame.K_DOWN:
        ship.moving_down=False
                
def update_screen(ai_settings, screen, ship):
    screen.fill(ai_settings.bg_color)
    ship.blitme()
    pygame.display.flip()

 elif event.type==pygame.KEYDOWN:
            check_keydown_events(event, ship)