python add to list

append(): append the object to the end of the list.
insert(): inserts the object before the given index.
extend(): extends the list by appending elements from the iterable.

Here is what the above code is Doing:
1. Creating a list with the elements 1, 2, 3, 4, 5.
2. Appending the element 6 to the end of the list.
3. Inserting the element 0 at the beginning of the list.
4. Extending the list by appending the elements 7, 8, 9.