I want to write using the 'shelve' module, but after entering 3 data, I can't enter anymore and the keys in the file are stored incorrectly

Question

I want to write using the 'shelve' module, but after entering 3 data, I can't enter anymore and the keys in the file are stored incorrectly ['3', '1', '2']. that's what happens on linux, and it's all good on windows

class BasicModel(ABC):
    table = '.db'

    def __init__(self):
        self.id = None
        self.created_date = None
        self.updated_date = None
        self.isValid = True

    def save(self):
        if self.isValid:
            path = getAbsolutePath(self.table)
            with shelve.open(path, writeback=True) as db:
                # Shu obj yangi yaratilayotgani
                if self.id is None:
                    self.created_date = datetime.now()
                    if list(db.keys()):
                        print(list(db.keys()))
                        self.id = int(list(db.keys())[-1]) + 1
                    else:
                        self.id = '1'
                else:
                    self.updated_date = datetime.now()
                db[str(self.id)] = self
        else:
            raise ValueError("Qiymatlardan biri noto'g'iri")

    def delete(self):
        with shelve.open(getAbsolutePath(self.table)) as db:
            del db[str(self.id)]

    def objects(table: str):
        with shelve.open(getAbsolutePath(table)) as db:
            for obj in db.values():
                yield obj

    @property
    def isValid(self):
        return self.__isValid

    @isValid.setter
    def isValid(self, value):
        self.__isValid = value


class Brand(BasicModel):
    table = 'Brands'

    def __init__(self, name):
        super().__init__()
        self.name = name