let archery_program = || { let mut notification = string::from("welcome to the pre-introductory archery session!"); let negate_no_go_zones = |zone| zone != "no-go"; let mut zones = vec!["target area", "no-go", "practice range"]; zones.retain(negate_no_go_zones); for zone in zones { notification.push_str(&format!(" {} is safe for practice.", zone)); } let reset_to_the_beginning = || println!("all archers reset to the beginning positions!"); reset_to_the_beginning(); notification };