Moving keys in the dopesheet via Python?

I’m trying to build a simple operator that selects left/right of the time slider and moves all the key by 1 frame (either left or right).

The selection bit is easy, just after checkin context:

bpy.ops.action.select_leftright(mode=“RIGHT”, extend=False)

but it seems I can’t get the transformation. Anyone can help?

Thanks,
Gian