We can create instances of the Party<AnimalElement> class by replacing the AnimalElement generic type parameter with any type name that conforms to the constraints specified in the declaration of the Party<AnimalElement> class. So far, we have three concrete classes that implement both the AnimalProtocol and Equatable protocols: Dog, Frog, and Lion. Thus, we can use Dog to create an instance of Party<Dog>--that is, a Party instance of Dog objects. The following code shows the lines that create four instances of the Dog class: jake, duke, lady, and dakota. Then, the code creates a Party<Dog> instance named dogsParty and passes jake as the leader argument to the initializer. This way, we will create a party of dogs, and Jake is the party leader. The code file for the sample is included in the swift_3_oop_chapter_06_03 folder:
var jake = Dog(name: "Jake")
var duke = Dog(name: "Duke")
var lady = Dog(name...