Can I create an immutable class attribute in Python 3?

Question

I am writing a class with custom __eq__ and __hash__ methods, and __hash__ basically returns one of class' attributes (which is an integer). Therefore, I need to make this attribute as immutable as possible. Is there a way to make an attribute immutable in Python?

I can, of course, make it __private, but that's not quite the same thing. Also at this point of time I am not sure if I should make my class a dataclass.

More context if this is somehow relevant: the class Simplex represents a combinatorial simplex, and stores a set of vertices (in the form of a binary number) and an integer coefficient. The class has a method boundary() that should return an object of the type Complex, which is a collection of Simplex instances. The __eq__ method thinks A == B if their sets of vertices coincide (coefficients are not relevant). The method __hash__ returns the binary storing vertices. I want __hash__ to work in this specific way, because I think it would simplify adding up equal simplices in Complex.

Answer 1

Try to use a customized class_property decorator.

Something like (copy from this post https://stackoverflow.com/a/5191224/24285005):

class ClassPropertyDescriptor(object):

    def __init__(self, fget, fset=None):
        self.fget = fget
        self.fset = fset

    def __get__(self, obj, klass=None):
        if klass is None:
            klass = type(obj)
        return self.fget.__get__(obj, klass)()

def classproperty(func):
    if not isinstance(func, (classmethod, staticmethod)):
        func = classmethod(func)

    return ClassPropertyDescriptor(func)


class Bar(object):
    @classproperty
    def bar(cls):
        return 1