Thanks guitarrista. That is it!
I'm not sure why my own research didn't bring up that.
It is probably Jonas' own arrangement, (or a colleague of his), like most of the other tracks on the recording.
I've listened to a few versions of the song on YouTube, including by Bob Dylan, but I'm not sure like them too much. They seem a little dour, whereas Jonas' version is very upbeat! I think it sounds quite nice that way.
I suppose if I want to play it, in Jonas' style, I'll have to arrange it myself. There are chords and the notes of the tune readily available.
"There is no duty we so much underrate as the duty of being happy.
By being happy we sow anonymous benefits upon the world."
Robert Louis Stevenson