maybe create an optional reference inside a map

maps.rs

fn get_or_insert1<'a>(map: &'a mut HashMap<String,String>, key:&String) -> &'a mut String {
    map.entry(key.clone()).or_insert_with(|| String::new())
}

fn get_or_insert2<'a>(map: &'a mut HashMap<String,String>, key:&String) -> &'a mut String {
    match map.get_mut(key) {
        Some(v) => v,
        None => {
            map.entry(key.clone()).or_insert(String::new())
        }
    }
}