Creating a set with dataclass and dict

[hobbitdur]

micseydel, thank you for your kind help.
But I am not sure I understood your answer.
You speak about using set in set or dict key. That's not what I meant.
My problem is the line 11 of my code. I have a dataclass that is Hashable (frozen and eq to True), but I cannot use it as an element of my set.

import collections
from dataclasses import dataclass


@dataclass(frozen=True, eq=True, repr=False)
class Building:
    name: str
    property: dict


foo = Building(name="Test", property={"key": 10})
print(isinstance(foo, collections.Hashable))
var = {foo}

Output:
F:/Perso/Python/board-game-solver/les-batisseurs/src/test.py:12: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.9 it will stop working
  print(isinstance(foo, collections.Hashable))
Traceback (most recent call last):
  File "F:/Perso/Python/board-game-solver/les-batisseurs/src/test.py", line 13, in <module>
    var = {foo}
  File "<string>", line 3, in __hash__
TypeError: unhashable type: 'dict'
True

Process finished with exit code 1

Thank you again !