Add List Items - Python Tutorial - w3Schools - Ch#20 English
Append Items
To add an item to the end of the list, use the append() method.
Insert Items
To insert a list item at a specified index, use the insert() method.
Extend List
To append elements from another list to the current list, use the extend() method.
Add Any Iterable
The extend() method does not have to append lists, you can add any iterable object (tuples, sets, dictionaries etc.).