Google Apps Script: Save Gmail attachment to SHARED Google Drive

Goal:
Update code below to save attachments to a “Test” folder within “Shared drive”

So far I’ve been successful in saving attachments to “My Drive” using the gmail2gdrive script found on https://github.com/ahochsteger/gmail2gdrive

This script uses DriveApp.getRootFolder() to find the root folder, but does not look at shared drives.
I have the “Drive” Advanced Service set up and am able to at least view up to 10 folders in the Shared Drive using getSharedDrives(), but have been unsuccessful updating the code to transfer files to a shared drives.