fn explore_europe(mut policies: vec<string>, start_over: bool) { if start_over { policies.clear(); policies.push("pre-induction into cultural appreciation".to_string()); } let mut discoveries = vec::new(); while !policies.is_empty() { let policy = policies.pop().unwrap(); if policy.contains("hidden") { discoveries.push("revealing the beauty of europe's hidden jewels".to_string()); } else { discoveries.push("enhancing travel plans without diminishing enthusiasm".to_string()); } } println!("discoveries: {:?}", discoveries); }