I agree that default arguments can (and should) be used for the backing list of your class.

In addition, consider inheriting from collections.abc.Sequence and delegating __getitem__ to the backing list. (Add other list-like methods as necessary.) This will make sure your class acts as a well-behaved list-like.

I agree that default arguments can (and should) be used for the backing list of your class.

In addition, consider inheriting from collections.abc.Sequence and delegating __getitem__ and __len__ to the backing list. (Add other list-like methods as necessary.) This will make sure your class acts as a well-behaved list-like.

In order to qualify as an Iterable, you must define __iter__ or __getitem__. In order to qualify as a Sequence you must be an Iterable that provides __getitem__ and __len__. It's up to you how much functionality you want to provide, but the Sequence ABC exists for a reason.