What is a gdmSpec object? How can I make it?

[pdkguru]

Dear All,

Hi! I'm trying to rename cell names in the specific library. But I'm
using the below SKILL sentences

libList = parseString(str "\n")
libSpecList = gdmCreateSpecList()
foreach(lib libList
spec = gdmCreateSpec(lib "" "" "" "CDBA")
gdmAddSpecToSpecList(spec libSpecList)
)

But I've got the below error message in the CIW.

*Error* gdmAddSpecToSpecList: argument #1 should be a gdm spec (type
template = "Gq") - nil

Does anyone know how to use the 'lib' field in the first argument of
gdmCreateSpec to make a gdmSpec object? And what is a gdmSpec object?
I've read the SKILL manual about it, but I didn't understand clearly
what that means and how to use it.

Thanks.