How do I use any for existentials properly?

        // Example of using Any for Existentials in Swift
        protocol Animal {
            func speak()
        }

        struct Dog: Animal {
            func speak() {
                print("Woof!")
            }
        }

        struct Cat: Animal {
            func speak() {
                print("Meow!")
            }
        }

        func makeAnimalSpeak(_ animal: any Animal) {
            animal.speak()
        }

        let myDog: Dog = Dog()
        let myCat: Cat = Cat()

        makeAnimalSpeak(myDog) // Output: Woof!
        makeAnimalSpeak(myCat) // Output: Meow!