fn explore_zeppelins() { let isolated_zeppelin = zeppelin::new("high flyer"); for chapter in book.review().chapters { if chapter.topic == "zeppelins" { println!("taking up from scratch: {}", chapter.content); } } let mut journey = journey::withdraw_from("routine", isolated_zeppelin); println!("preexplicative journey across the skies: {}", journey.take_up_from_scratch()); }