Serious question: why would you write your own device type Handler for a basic switch? There’s already a generic Z wave handler for that.
Normally people write their own device type handlers for one of two reasons:
One) the device offers advanced features which are not accessible through any of the existing device type handlers or
Two) you want to change The look of the UI for the device.
And again, most of what goes in the fingerprint is going to be sent by the firmware in the device itself. You as a coder shouldn’t have to do anything about it except capture it.
If you’re creating a hardware device, then you have to worry about setting up the fingerprint. But if you’re just using an existing device that you purchased, the fingerprint comes with the device.