ex42.py

## Animals is-a object (yes look at the extra credit
class Animal(object):
	pass
	
class Dog(Animal):

	def __init__(self, name):
		self.name = name
		
class Cat(Animal):

	def __init__(self, name):
		self.name = name
		
class Person(object):

	def __init__(self, name):
		self.name = name
		self.pet = None
		
class Employee(Person):

	def __init__(self, name, salary):
		super(Employee, self).__init__(name)
		self.salary = salary
		
class Fish(object):
	pass
	
class Salmon(Fish):
	pass
	
class Halibut(Fish):
	pass
	
rover = Dog("Rover")
satan = Cat("Satan")
mary = Person("Mary")
mary.pet = satan
frank = Employee("Frank", 120000)
frank.pet = rover
flipper = Fish()
crouse = Salmon()
harry = Halibut()