Sorry, I was not clear enough. I come from the C++ world, where it is natural that types are checked at compile time. And where you would use classes to implem

Sorry, I was not clear enough. I come from the C++ world, where it is natural that types are checked at compile time. And where you would use classes to implement the 'sophisticated types' the author suggested. So in the ears of a C++ programmer the article says: design your classes well.