Another way of putting this would be: "Make map() statements as simple as possible by adding methods to the objects being mapped over". This makes sense except

Another way of putting this would be: "Make map() statements as simple as possible by adding methods to the objects being mapped over". This makes sense except when the elements being mapped over are built-in and library-types which you can not add methods to. But in that case I would suggest add the methods to the class containing the mapping-code.