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# need help cant figure out how to add the three parameters at once

i know that reversing the list by every three numbers should be like list_name[::-3] since list_name[::-1] reverse the list by one item each time

lists.py
```messy_list = [5, 2, 1, 3, 4, 7, 8, 0, 9, -1]

# Your code goes below here
clean_list = messy_list[:]
clean_list.sort()
```

MOD

You have the correct answer (be sure to be slicing `messy_list` on Task 3):

```#    lists.py

messy_list = [5, 2, 1, 3, 4, 7, 8, 0, 9, -1]

# Copy messy_list using slice syntax into a new variable clean_list.
clean_list = messy_list[:]

# Sort clean_list using the sort() method.
clean_list.sort()

# Now, create a variable named silly_list that is every third item, backwards, from messy_list. For example, the first two items in silly_list should be [-1, 8].
silly_list = messy_list[::-3]
```

Hi Chris Freeman,

I did just that and it never worked, let me try again.

Given the three indexes, start, stop, and step, the stop must be larger than the start or there will be no list to step through:

```>>> messy_list[9:0]
[]
>>> messy_list[9:9]
[]
```
```silly_list = messy_list[-1::-3]
```