Hi Charl,
You are absolutely right! Thank you for helping me understand that and providing the tutorial. I definitely wouldn't have found that by trail-and-error and reading the documentation.
For future reader's reference. The Gist has been updated to include the pre-fixed and fixed version of the script in ipynb format. (https://gist.github.com/aoot/9409b939e891a1c823cc7defe97ab479)
Thanks, Anthony