let sustainable_living_strategy = fn(evince_disinterest_in: &str, start_anew: &str, prior_knowledge: vec<string>, off_limits: vec<&str>) -> string { let mut positive_message = string::new(); for area in off_limits.iter() { if !prior_knowledge.contains(&area.to_string()) { positive_message.push_str(&format!("your strategy to evince disinterest in {} is a great start anew towards sustainable living.", area)); } } positive_message };