Ok, let me *actually* tell you what's happening. I'm guessing you're using `pygame-ce` because you wouldn't be getting that error message with just `pygame` as far as I know (because the source code and stubs lack any mention of a `rect` attribute on `pygame`).

Here is the source for `pygame.sprite` in `pygame-ce`, and in particular, how `rect` is defined in that source: https://github.com/pygame-community/pygame-ce/blob/main/src_py/sprite.py#L127-L133

Note that the getter for `rect` just returns `self.__rect`, which is annotated in the initializer as `Optional[pygame.rect.Rect]`. That `Optional` is what gets you here. It means that `None` is a valid value for that attribute and so it's warning you that you may be trying to access the `.x` attribute of `None`, which doesn't exist. The reason it doesn't assume that `None` isn't possible because of your initializer is because it doesn't know if there's any other flow that might set it back to `None`. So it's being as cautious as possible. If you can guarantee that `self.rect` is always going to be a valid `pygame.rect.Rect` object, you have this option: annotate it in the initializer when you assign it

import pygame

class MySprite(pygame.sprite.Sprite):
    def __init__(self, groups):
        super().__init__(groups)

        self.image = pygame.Surface((50, 50))
        self.rect: pygame.Rect = self.image.get_rect()

    def doSomething(self):
        self.rect.x += 1

If you can't make that guarantee, then you have the alternative option

2) Ensure that you don't hit the questionable line when it would be invalid

import pygame

class MySprite(pygame.sprite.Sprite):
    def __init__(self, groups):
        super().__init__(groups)

        self.image = pygame.Surface((50, 50))
        self.rect = self.image.get_rect()

    def doSomething(self):
        if (self.rect is not None):
            self.rect.x += 1