You Are My Sunshine was copyrighted by
Jimmie Davis and
Charles Mitchell in 1940, but its true writer is unknown.
It's one of the state songs of Louisiana.

This is how the melody begins. The lyrics famously assigned to this phrase are "You are my sunshine, my only sunshine.."

These are the chords I'm playing on bars 5 & 6. The first one is in fact A69, and then the second one is A6 as the chord signature says. Moving to the next bar, we first have B+7 (pronounced
B augmented seven), and the second one is F#dim7 (pronounced
F# diminished 7).

And this is what I'm playing at the first turnaround of the melody. We have an A7 - Bbdim7 - A/B progression, before going back to E. This Bbdim7 in the middle is a #IV diminished chord often found in a bluesy context.