Should Python snippets be updated for (or checked against) Python 3?

[dato]

Hi—

Now that Python 3 is widely used, it might be a good idea to ensure Python snippets work with this version?

I’m submitting this issue mostly just to verify if you’d accept a PR; I might have time to work on this.

In many cases, changes are somewhat cosmetic only, like "crypto101" → b"crypto101" in the hashing examples.

[lvh]

I'd be happy to accept a PR but last I checked plenty of changes get quite a bit more complicated -- like indexing a bytearray resulting in an int, not a bytearray of length 1. But sure, I'd be fine with Python3-first :)