A simple record class that can be made immutable (frozen) but also behaves like a mutable named tuple when not frozen

FreezableRecord.py

from types import SimpleNamespace


class FreezableRecord(SimpleNamespace):
    """ A simple namespace record class that allows attributes to be made immutable (frozen) after creation 
			Must be initialized with allowed attributes at creation via **kwargs
			Behaves somewhat like a namedtuple in that once initialized, new attributes are not permitted,
			however, unlike a nametuple, attribute values are mutable (unless frozen)
			Attempt to set a new attribute after initialization will raise AttributeError """

    def __init__(self, **kwargs):
        self.__frozen = False
        super().__init__(**kwargs)
        self.__init = True

    def __setattr__(self, name, value):
        # if instance is being initiliazed, allow any attribute to be set
        # if instance not frozen, allow only existing attribute to be set
        # if frozen, don't allow any attributes to be set

        frozen = f"_{type(self).__name__}__frozen"
        init = f"_{type(self).__name__}__init"
        if (
            frozen in self.__dict__
            and self.__frozen
            and name in self.__dict__
            and name != frozen
        ):
            # frozen and trying to set allowed attribute
            raise AttributeError("Cannot set attribute while frozen")
        elif init in self.__dict__ and name not in self.__dict__:
            raise AttributeError("Cannot set new attributes after __init__")
        else:
            super().__setattr__(name, value)

    def freeze(self):
        self.__frozen = True

    def thaw(self):
        self.__frozen = False


def main():
    rec = FreezableRecord(x=None, y=None)

    # attribute values are mutable
    rec.x = 1
    rec.y = 2

    # repr inherited from SimpleNamespace
    print(rec)

    # but cannot add new attributes
    try:
        rec.z = 3
    except Exception as e:
        print(f"Caught exception creating new attribute: {e}")

    # freeze
    rec.freeze()

    # now values are immutable
    try:
        rec.x = 3
    except Exception as e:
        print(f"Caught exception setting during freeze: {e}")

    # still can't add a new attribute
    try:
        rec.z = 3
    except Exception as e:
        print(f"Caught exception creating new attribute: {e}")

    # thaw
    rec.thaw()

    # attributes are now mutable again
    rec.x = 3
    print(rec)

    # nice __eq__ inherited from SimpleNamespace
    rec2 = FreezableRecord(x=3, y=2)
    print(rec == rec2)  # True


if __name__ == "__main__":
    main()