Controlling whether subclasses can or cannot override members

The following lines show the code for the complete Dog class that inherits from DomesticMammal. Note that the following code replaces the previous Dog class that just declared an overridden type property:

public class Dog: DomesticMammal {
    public static override var numberOfLegs: Int {
        get {
            return 4;
        }
    }
    
    public static override var abilityToFly: Bool {
        get {
            return false;
        }
    }
    
    public var breed: String {

        get {
            return "Just a dog"
        }
    }
    
    public var breedFamily: String {

        get {
            return "Dog"
        }
    }
    
    private func initializeDog() {
        print("Dog created")
    }
    
    public override init(age: Int, name: String, favoriteToy: String) {
        super.init(age: age, name: name, favoriteToy: favoriteToy)
        initializeDog()
    }
    
    public override init(age: Int...