I have the following string:

```
s = 'HELLOPEOPLE'

```

How would I get all words made up of consecutive letters in the above word between length a and b? For example:

```
get_words('HELLOPEOPLE', min=2, max=3)
==> he, el, ll, lo, op, pe, eo, pl, le, hel, ell, llo, lop, peo, epl, ple

```

Initially I thought to use `chain.product`, but that doesn't obey ordering of letters (as far as I could tell).