python slot

slot.py

class Car:
    """
    Regular classes use a __dict__ for attributes
    """
    def __init__(self):
        self.brand_name = "hyundai"


class ECar:
    __slots__ = ("brand_name", )  # this will prevent declaration of new slots
    __dict__ = {"brand_name": "kia"}

    def __init__(self):
        self.brand_name = "kia"


if __name__ == "__main__":
    import tracemalloc

    tracemalloc.start()

    a = Car()
    # a.price = 1000
    print("current memory: {} \n peak memory: {}".format(*tracemalloc.get_traced_memory()))

    tracemalloc.stop()

    del a

    tracemalloc.start(10)

    b = ECar()
    # b.price = 1000
    # print(b.__dict__)

    print("current memory: {} \n peak memory: {}".format(*tracemalloc.get_traced_memory()))