Here's what a[1:4].reverse() actually does:

create a sublist (slice) of a, so a[1:4] == [1, 2, 3]
reverse that list in-place, so it's now [3, 2, 1]
throw that list away because you didn't ask it to do anything with it
I have a list, a = [0,1,2,3,4,5].
I'm trying to reverse the slice a[1:4], with a[1:4].reverse(). However, the value of a does not change. Why does this happen?
Note: I don't want to know how to make this work - rather, why this happens.
Why is reverse() on specific slice of a list not working?