I'm guessing that when you ask how to 'refresh' the module you might have run into the following situation: you edited a copy of the module but when you 'use' it in some script it still isn't aware of the new function(?)
Two possible problems come to mind:
- You haven't exported the new function or specifically requested in in the script that uses the module. There is a good write-up here on writing modules, where you can find out more about exporting.
- You have exported the function but it still isn't picked up because the original module is actually installed on your system and that is the version that will get loaded when you 'use' the module - not your local copy. You need to find out where it is installed so you can update the installed version. Check for example here for how to do that. If you aren't using some kind of version control system to trace changes I would strongly recommend you do so before updating installed modules.