save project

my_game.py

@@ -80,7 +80,7 @@ while True:
         num = random.randint(0,50)
         if num > 20:
             obstacle=Block(bush,cacti,stone)
-            block_list.add(obstacle)
+            block_list.add(aa)
     for sprite in block_list:
         sprite.rect.x-=8
         screen.blit(sprite.image, (sprite.rect.x, sprite.rect.y))