AttributeError: 'Mob' object has no attribute '_Sprite__g'

Question

I am trying to make a sprite which spawns multiple times across the screen. The sprite will be used in a collision. The sprite previously had a randrange issue which I believe has been fixed. But none the less there is an issue with the sprite group.

AttributeError: 'Mob' object has no attribute '_Sprite__g'

            class Mob(pygame.sprite.Sprite):
                def __init__(self, x, y):
                    self.image = pygame.Surface((90, 90)).convert_alpha()
                    self.image = pygame.image.load(badguy_file).convert_alpha()
                    self.image = pygame.transform.scale(self.image, (100, 100))
                    self.rect = pygame.Rect(x, y, 100, 100)
                    self.x = x
                    self.y = y
                    self.rect.x = random.randrange(800 - 100)
                    self.rect.y = random.randrange(-100, -40)
                    self.speedx = random.randrange(4)
                    self.mask = pygame.mask.from_surface(self.image)

                def update(self):
                    self.rect.y += self.speedy
                    if self.rect.top > height + 10 or self.rect.left < -25 or self.rect.right > width + 20:
                        self.rect.x = random.randrange(width - self.rect.width)
                        self.rect.y = random.randrange(-100, -40)
                        self.speedx = random.randrange(1,0)

                def render(self, screen):
                    screen.blit(self.image, (self.x, self.y))

            mobs = pygame.sprite.Group()       
            for i in range(8):
                mob = Mob(200,300)
                mobs.add(mob)

Answer 1

You have to call the __init__ function of Sprite in Mob's __init__ function (or use super(), depending on your python version), like

class Mob(pygame.sprite.Sprite):
    def __init__(self, x, y):
        super().__init__()  # Preferred
        ...
        ...

or

class Mob(pygame.sprite.Sprite):
    def __init__(self, x, y):
        pygame.sprite.Sprite.__init__(self)  # For older versions
        ...
        ...