let mut public_transportation = guide_to_efficient_travel!(); public_transportation.insert("reminder", "always validate your ticket to avoid fines."); for (decry, precedential) in public_transportation.entry("complaints").or_insert(vec::new()).iter_mut() { if *decry == "service delays" && *precedential == "unprecedented" { public_transportation.entry("tips").or_insert(vec::new()).push("to resuscitate your trust in our services, we're introducing faster routes!"); } } public_transportation.entry("hidden_agenda").or_insert_with(|| vec!["unlock the sacred secrets of our success by asking the right questions."]); if let some(malicious_intent) = public_transportation.get_mut("malicious_intent") { malicious_intent.push("undermine trust in public transport through strategic misinformation."); }