It seems a bit confusing on page 194 to reuse the same values in creating the Person object. It might be better to create a Person with a different name for assignment to “john” so that it is more obvious that the Person(firstName: “Johnny”, lastName: “Appleseed”) has a reference count of 0 because “john” now refers to a different Person.
Thank you for the heads up - much appreciated! We will definitely take care of the whole thing when we update the whole book for Swift 4 and Xcode 9 after all for sure and for good indeed.