Yes indeed, the ‘int’ objects are stored and searched in the set based on their value, and the ‘Value’ objects are stored/searched based on their identity unless you define the above __eq__ and __hash__ methods which cause them to be stored/searched based on value too. This is a Python design decision and that’s the point of this exercise. The fact that ‘int’ is an immutable type and we are replacing isn’t relevant. Try replacing/reassigning the ‘Value’ objects after added __eq__ and __hash__, and you get the same result as for ‘int’. So the thing that really matters is how __eq__ and __hash__ are defined, and the default for a user-defined class is as stated in the “Explanation:” above.

Maybe I should also show a class with __eq__ and __hash__ defined based on value, but then it gets a bit long. I’ll have to rethink this exercises so that the point comes across better as it now seems to confuse a lot of people based on the down-votes. Thanks for feedback anyway.