Hello, I do not know if this is a "good" sample, which would be subjective, but this is my sample (I do not use Libraries at this time because HPM does not yet support it):
I own an app that I recently updated to rely on another file.
However, since HPM does not support libraries (yet), I just amalgamated my app code with the other file I needed: https://github.com/akhandok/adhanPlayer/blob/4.0/app.groovy#L300
If libraries were possible, I would break these up into the app.groovy
for the Hubitat app code and the library that I need for computations/helpers.