if _ is _或.isKind(of：)的正确用法是什么？

class Animal {}
class Dog: Animal {}

let animal = Animal()
if animal is Dog {
    print("animal is a dog")
} else {
    print("animal is not a dog")
}

class Animal {}
class Dog: Animal {}

let animal = Dog()
if animal.isKind(of: Animal.self) {
    print("animal is an animal or its subclass")
} else {
    print("animal is not an animal or its subclass")
}