Please don't use `unwrap`!

[killf]

Please don't use unwrap, this code:

        #[allow(unused_parens)]
        pub fn $name($($arg: $argtype),*) -> $ret {
            let key = ($($arg.clone()),*);
            {
                let mut cache = $cachename.lock().unwrap();
                let res = $crate::Cached::cache_get(&mut *cache, &key);
                if let Some(res) = res { return res.clone(); }
            }
            let val = (||$body)();
            let mut cache = $cachename.lock().unwrap();
            $crate::Cached::cache_set(&mut *cache, key, val.clone());
            val
        }