static REMOVE_SEPARATORS: OnceLock<Regex> = OnceLock::new();
        let remove_seps =
            REMOVE_SEPARATORS.get_or_init(|| Regex::new(r"(\A|\s)[-+/\\:](\z|\s)").unwrap());
        let subtype = subtype.as_ref().trim().to_lowercase();
        let subtype = remove_seps.replace_all(&subtype, " ");

                .as_ref()
                .trim()
                .to_lowercase()

            Arc::from(subtype.as_ref().trim().to_lowercase()),

            Arc::from(subtype),

("mad:dot / dasher", "mad-dot - dasher", "mad:dot - dasher")

("mad:dot dasher", "mad-dot dasher", "mad:dot dasher")