Produce movable C++ code

How can I write some code (only functions-no actor dependency or so) that can be moved into a blueprint only project? (it will be accesed through blueprints). For example some code that reads through a specific file format and returns some data?

if you create a class inheriting from BlueprintFunctionLibrary, you can fill it with static functions that can be accessed from any blueprint. its also a good place to put Enums and Structs that you want to use in a lot of different blueprints.