I usually use classes similarly to how one might use `namedtuple` (except of course that the attributes are mutable). Moreover, I try to put lengthy functions in classes that won't be instantiated as frequently, to help conserve memory. 

From a memory point of view, is it inefficient to put functions in classes, if it is expected that the class will be instantiated often? Keeping aside that it's good design to compartmentalize functionality, should this be something to be worried about?