>That's basically what java and python do. Well, they can be tricky too. But,you can easily make the classes/collections immutable to avoid the issues you ment

>That's basically what java and python do. Well, they can be tricky too. But,you can easily make the classes/collections immutable to avoid the issues you mentioned. I think in java records and many collections are immutable by default. Immutability is fundamental to functional style programming.