option taking optional argument `-u1` with getopts

[hancooper]

Have been using getopts to pass arguments to a function. I would like that the 
option -u takes an optional
argument `-u1`. I wonder how I can implement this thing.

local OPTIND OPTARG
local shortopts="Vuhs"
while getopts $shortopts arg; do
case $arg in
("V")
pfm "V01 Jul 2021 Wk27 Matematiker Christopher Dimech"
return
;;
("u")
pfm -- "-V, -h, -u"
pfm "TITLE ASC"
return
;;
esac
done