func isLeapYear(_ year: Int) -> Bool {
    if number(year, isDivisibleBy: 4) {



        if number(year, isDivisibleBy: 100) {





            if number(year, isDivisibleBy: 400) {
                // Fill in this code...
                return true
            } else {
                return false
            }







            return false
        } else {
            return true
        }



        return true
    } else {
        return false
    }
}