ArrayHomogeneity

        class Dog {
            var name: String
            init(name: String) {
                self.name = name
            }
        }
        
        class Chihuahua: Dog {
            
            override init(name: String) {
                super.init(name: name)
            }
        }
        
        let dog = Dog(name: "max")
        let chihuahua = Chihuahua(name: "sam")
        
        let array = [dog, chihuahua]