SK
 Human {
    var name = "Steven"
    var age: Int? = 30
    var hairs = true
    var hairColor = "Black"
    
    func description() -> String {
        if let humanAge = age {
            return "Hello! My name id \(name) and !`am \(humanAge) years old!"
        } else {
            return "Hello! My name id \(name)"
        }
//        guard let manAge = age else {
//            return "Hello! My name id \(name) and !`am \(manAge) years old!"
//        }
    }
}
        
      
      
