I thought I had seen a few occurrences of missing braces, so I was wondering if you changed style at some point. Then I looked at the core Python style, and it doesn't require braces AFAIK. So I went for the "optional" style, as it fits more on one editor screen. Will fix.

Just a side-note to make your life easier: when there are multiple occurrences of a code comment, it's enough to comment on the first one, possibly with a "here and everywhere" suffix, and I'll do the change everywhere.