The `append_sum`

function is one that you should write, not one that is built-in. Although loops would make the implementation of this more efficient, you can just as easily solve this exercise without them.

These 2 expressions:

```
lst[-1:]
```

and

```
lst[-2:-1]
```

take slices of `lst`

. They do return the last and second-last elements of the list, respectively. However, they return **list slices**, and not the **elements themselves**. This means that `value`

does not store the sum of the last two elements, but rather combines the two list slices into one list.

##
Example

```
lst = [0, 1, 2, 3, 4]
combined = lst[0:1] + lst[4:]
print(combined) # prints [0, 4]
added = lst[0] + lst[4]
print(added) # prints 4
```

What changes could you make to get the correct result?