protocol_04.swift

protocol Blendable {
  func blend() -> ()
}

class Fruit: Blendable {
  var name: String
  
  init(name: String) {
    self.name = name
  }
  
  func blend() {
    print("Almost all friut can be used")
  }
}

class Dairy {
  var name: String
  
  init(name: String) {
    self.name = name
  }
}

class Cheese: Dairy {
  //we cannot use cheese to make smoothie
  //so no blendable protocol implemented
}

class Milk: Dairy, Blendable {
  
  func blend() {
    print("Milk is a type of dairy")
  }
  
}