I am using a library that in early versions has a function declaration

I have a map that is part of an object that I want to make sure that I never accidentally mess up; however, when compiling, I get the following error:

I am aware of the general guideline “Do not use const inside classes,” but I have encountered situations where I am unsure about the proper declaration of variables. For example, consider the following code:

Consider the following code (which hides all spheres in a collection from the scene):