From: "Guido van Rossum" firstname.lastname@example.org
As I indicated in my previous mail, I didn't expect any other result.
Then your question was formulated strangely. You showed the result and said "how does it know that list items are immutable"; the context suggested strongly to me that you had expected something else.
My question was about what a new type needs to do in order for things
work properly in Python.
You could have asked that directly. :-)
Incorrect background assumptions have a way of fouling communication. I hope it's obvious that I'm making an effort to be clear.