pub fn complete_val<'a, O, I, F>( arg: &str, bytes: &[u8], opts: I, values: &HashMap<Uid, Box<dyn Values<O, Err = Error>>>, f: F, ) -> Result<bool, Error>where O: Opt + 'a, I: Iterator<Item = &'a O>, F: FnMut(&OsStr, &O) -> Result<(), Error>,