since print() was made a function in py3, i can predict at some point
that return will be made a func as well. sure, good.
but "return()" *currently* returns an empty tuple. We want to
explicitly return None for testing purposes.
turns out ALL of the disk operations can be performed with
gobject-introspection.
BUT it's unlikely that that'll be available everywhere, or that
the Arch Linux releng team would include it, etc.
So we have fallbacks to mimic it.
BUT please try to use gobject-introspection with libblockdev,
because it's going to be a lot faster and a lot less error-prone.
