When is it appropriate to Subclass built-in data types in Python?

Question

Overview

This question is regarding subclassing built-in data types in Python; for example:

class MyList(list):
    def __init__(self, *args):
        super().__init__()


class MyDict(dict):
    def __init__(self, *args):
        super().__init__()



my_list = MyList()
my_dict = MyDict()

Note : This is just an example; my question is for any built-in data types in general, not just list and dict data-types.

Questions

1. What are the pros and cons of subclassing built-in data types like this?
2. Is this recommended Python practice?
3. Would there ever be a case to use super() when subclassing built-in data types like this?
4. Can you please give a code examples of how to correctly implement a list and dict built-in data subclass?

Answer 1

My advise is to use UserDict and UserList from collections module as starting point:

UserDict : https://docs.python.org/3/library/collections.html#userdict-objects

UserList : https://docs.python.org/3/library/collections.html#userlist-objects