I never got a reply, but your timing is funny as I was just researching this again a couple of days ago.
Basically, you need to be able to add a custom package to your Gateway, which this post outlines. I chose Mako for templating, but there are many Python templating options available.
Next, take the downloaded package, unzip it and copy it to the pylib directory mentioned in the link above.
Finally, to test, you can use the script console in the Ignition Designer.
Hope this helps.
*** Update **
Unfortunately, we are running into issues when attempting to import this into a Web Dev Python resource file. It seems to be in line with this post.