Pygame Tutorials - Sprite Module Introduction — pygame v2.6.0 documentation

class RenderUpdatesDraw(RenderClear):
    """call sprite.draw(screen) to render sprites"""
    def draw(self, surface):
        dirty = self.lostsprites
        self.lostsprites = []
        for s, r in self.spritedict.items():
            newrect = s.draw(screen) #Here's the big change
            if r is 0:
                dirty.append(newrect)
            else:
                dirty.append(newrect.union(r))
            self.spritedict[s] = newrect
        return dirty