class Vault2:
    def __init__(self):
        self._treasure = "gold"
        self._original_dict = dict(self.__dict__)

    def __setattr__(self, name, value):
        if name != "_treasure" and name in self.__dict__ and self._original_dict.get(name) != value:
            print("attribute deleted!")
        self.__dict__[name] = value

    @property
    def treasure(self):
        if self.__dict__ != self._original_dict:
            print("attribute deleted!")
        return self._treasure
v = Vault2()
print(v.treasure)