游戏问题

import pgzrun
WIDTH = 750
HEIGHT = 400
bg = Actor(“背景4.png”)
target = Actor(“手杖.png”, [700, 210])
hero = Actor(“骑士0.png”, [50, 210])
success = Actor(“成功4.png”, [800, 800])
c = Actor(“云朵.png”, [415, 100])

def draw():
bg.draw()
target.draw()
c.draw()
hero.draw()
success.draw()
def on_mouse_down():
y = c.y
y = y + 15
c.y = y
hero.speed,hero.num, hero.change,flag = 1,0,1,0
def update():

global flag
hero.num += hero.change
hero.image = "骑士" + str(hero.num % 28) + ".png"
hero.x += hero.speed
hero.speed = 1
if 367 <= hero.x <= 464 and c.y >= 235 and hero.y < c.y:
    hero.bottom = c.top + 5
    if c.y > 280:
        flag = 0
    else:
        flag = 1
elif 367 <= hero.x <= 464 and c.y < 235:
    if c.y>= 190:
        hero.speed = 0
if flag == 1 and hero.x > 464:
    hero.y = 210
if flag == 0 and hero.x > 464: 
    if 280 < c.y <= 330 and hero.y < c.y:
        hero.bottom = c.top + 5
        hero.speed = 0
    else:
        hero.y += 5
if 367 <= hero.x <= 464 and hero.y > c.bottom:
    hero.y += 5
if hero.colliderect(target):
    success.pos = [375, 200]
    hero.speed, hero.change = 0, 0

pgzrun.go()

我空行的里面是我想问的代码
我的问题是：不知到什么意思