class Starship: captain: str = 'Picard' damage: int stats: ClassVar[Dict[str, int]] = {} def __init__(self, damage: int, captain: str = None): self.damage = damage if captain: self.captain = captain # Else keep the default def hit(self): Starship.stats['hits'] = Starship.stats.get('hits', 0) + 1 enterprise_d = Starship(3000) enterprise_d.stats = {} # Flagged as error by a type checker Starship.stats = {} # This is OK