Scripting Equivalent (ERL?)

[calebmillerkb3]

I am looking for information about creating a plugin. I've found an outdated python script for blender that scales an object based on known perpendicular planes for distorted models, and would like to come up with an equivalent for wings.

Addon functionality: choose three faces on selection whose normals /should/ be perpendicular to each other. Addon automatically scales/shifts/shears selection to approach perpendicularity using matrix operations. The original python script is attached below.