Default Material in HFSS

I am attempting to make a python script that will take the Materials in the UserLib directory and move them to the configured libraries. After moving the configured libraries, I want to set that as the default. How would I go about doing this? I have the ability to move the Materials to the UserLib, but do not know how to make that as the default.

Perhaps there is an xml file that defines the configured libraries, or a method parameter in the DefinitionManager.

Thanks in advanced for the help.