Build a Validated field

Implement a data descriptor Validated(min_value, max_value) usable as a class attribute: - stores the value under a mangled name chosen in __set_name__ - __set__ raises ValueError when the value is not an int or is outside [min_value, max_value] - __get__ on the class (obj is None) returns the descriptor itself - the class access must expose the declared bounds: Model.age.min_value == 0

Difficulty: advanced