Access multicore details via API (plugin)

For a DRC plugin I need some information from the multicores.

I access the multicores with the API.

I need the multicore details.

To check if the multicore is sheathed or twisted, I can easily use the attribute "SheathType".

But is there a way to check if the multicore is "In House" true or false?

I cant find any attribute or method to access this Information.