In Python one can use array slice notation to get a subset of values in an iterable:

```
a = [0,1,2]
a[0:2]
# returns all members from the 0th to the 2nd: [0,1]

```

If you attempt to extract a slice where the first value is negative, and the second value is positive, however, the request returns an empty list:

```
a[-1:2]
# returns []

```

This is counterintuitive to me, as the range defined by -1:2 seems to be a *superset* of the range defined by 0:2.

I know one can use negative indexes to pluck from the end of an array with Python slice notation (ex: `a[-1]` is 2), but it seems like a negative value in the first slice position and a positive in the second should either raise an error or return a superset of the values returned by the same slice with a 0 in first position.

I'd be curious to know the motivation behind the empty list returned by slice requests with a negative value in the first position with a positive value in the second if anyone happens to have insight on this front...