Most semi-primitive types in python is immutable, yes (int, float, char, str, and DateTime), but all of the collections are mutable (List, Dict, Set). I'm sure

Most semi-primitive types in python is immutable, yes (int, float, char, str, and DateTime), but all of the collections are mutable (List, Dict, Set). I'm sure there are immutable versions of those same data structures hidden somewhere in the standard library, but I haven't looked. I did stumble upon pyrsistent (https://github.com/tobgu/pyrsistent https://github.com/tobgu/pyrsistent) a while ago which does provide proper immutable (and persistent) data structures for python.