This script automates the steps Nick Chamberlain had to take in Week 5 / Section 4 (he asked if there was a "better way") of RebelWay's 'Cinematic Lighting in Houdini' course. This script requires no changes to the 'Asset Reference' node itself, it adds the needed categories and sub-categories and sets the primpath for you.

This script should be placed in your scripts directory, inside another directory called lop. The Houdini scripts directory is usually in the same location as your houdini.env file. On Windows this is usually C:\Users\yourname\Documents\houdini20.0\scripts\lop. On Mac it is usually /Users/yourname/Library/Preferences/houdini/20.0/scripts. (replace 20.0 with your Houdini version)