Text align in a span

Hi All,
I’m trying to get my head around using LVGL with Micropython. My specific question is:
How do I make text justified to the right (align right) in a span? I’ve tried variations along the lines of
cpsnum = lvgl.spangroup(scr)
cpsnum.set_align(cpsnum, lvgl.ALIGN.RIGHT) to no avail.

More generally, how am I supposed to figure this stuff out when all the documentation is for the C version of LVGL? What am I missing?