>> Should I add a note to explain why the loop argument has to be explicitly
passed? (there is a note at the beginning of the `task functions` section
stating "In the functions below, the optional loop argument ...")

> Oh, that's a good idea. It's sort of clear because it starts with "from a
different thread" but it doesn't hurt to say the same thing in different
ways, because it's an easy mistake to make.

Can we make 'loop' a required argument (no default None value)?