Instructions
Reverse a string

For example: input: cool output: looc

In python, please explain why the ::-1

def reverse(text):
    return text[::-1]
The slice notation, or the `[]` part after an array such as a string in Python, uses the following syntax:
```python
array[start:stop:step]
```
It slices the array from index `start` to index `stop - 1` by skipping `step`. For example:
```python
arr = '12345678'
print(arr[1:7:2])
```
The output will be `246`. The notation doesn't have to be fully filled, as there are default values. For example:

- `array[start:]` slices from index `start` to the end.
- `array[:stop]` slices from the beginning to index `stop - 1`.
- `array[start::step]` slices from index `start` to the end by skipping `step`.

Therefore, `array[::-1]` can be understood as slicing the whole array by skipping -1, which means it is stepping backwards from the end to the beginning, thus reversing it.
Given a string, produce a new string that is comprised of every third character from the original string. Then, reverse it and print it.
Here's an example implementation in Python:

    def split_every_third(string):
        return string[::3][::-1]
    
    input_str = This is a test
    print(split_every_third(input_str))

Running this code should produce the output s ssT because it takes every third character (starting from index 0) from the original string, which would be Tss s and then reverses it to produce s ssT.