Documentation Clarification on lists

According to the ["Modelling" Data docs](https://docs.hivedb.dev/best-practices/modelling_data#lists-vs-auto-increment), it says:
> If you want to store a list of items, you have two options. Either store the list directly as a value (using put('myKey', [1, 2, 3])) or you can store each item individually (using add(1), add(2) etc.).
>
> If you want to store a big list which is updated frequently (for example a list of messages), you should store the items individually. Otherwise the whole list has to be written each time you change an item.

Could you indicate the structure of the data for each of these operations? I understand the first option to have a structure like so.
```json
{'myKey': [1, 2, 3]}
```
but not what the structure of the second would be.