Разница между датами

func calcDiff(between start: String, and end: String ) -> String {
        if
            let endTime = Date.from(end),
            let startTime = Date.from(start)
        {
            return Calendar.current.date(from: Calendar.current
                .dateComponents([.hour, .minute], from: startTime, to: endTime))?
                .formatted("HH:mm") ?? "--:--"
        }
        
        printError("Can't convert time ")
        return  "--:--"
    }