# generics/DogsAndRobots.py
# (c)2017 MindView LLC: see Copyright.txt
# We make no guarantees that this code is fit for any purpose.
# Visit http://OnJava8.com for more book information.

class Dog:
    def speak(self):
        print("Arf!")
    def sit(self):
        print("Sitting")
    def reproduce(self):
        pass

class Robot:
    def speak(self):
        print("Click!")
    def sit(self):
        print("Clank!")
    def oilChange(self):
        pass

def perform(anything):
    anything.speak()
    anything.sit()

a = Dog()
b = Robot()
perform(a)
perform(b)

output = """
Arf!
Sitting
Click!
Clank!
"""