Initialization of classes without any constructor in Swift

let nokiaPhone = Phone();
nokiaPhone.model = "Nokia 6610"

let iPhone5 = Phone();
iPhone5.model = "iPhone 5"

let kim = Employee()
kim.firstName = "Victorya"
kim.lastName = "Kim"
kim.personalPhone = iPhone5

class Phone {
    var model: String?
}

class Employee {
    var firstName: String?
    var lastName: String?
    var personalPhone: Phone?
}