## Animal is-a object (yes, sort of confusing) look at the extra credit
class Animal(object):
    pass


## Dog is-a Animal
class Dog(Animal):
    def __init__(self, name):
        ## Dog has-a name
        self.name = name

        
## Cat is-a Animal
class Cat(Animal):
    def __init__(self, name):
        ## Cat has-a name
        self.name = name

        
## Person is-a object
class Person(object):
    def __init__(self, name):
        ## Person has-a name
        self.name = name
        ## Person has-a pet of some kind
        self.pet = None

        
## Employee is-a person
class Employee(Person):
    def __init__(self, name, salary):
        ## heritage from parents
        super(Employee, self).__init__(name)
        ## Employee has-a salary
        self.salary = salary

        
## Fish is-a object
class Fish(object):
    pass


## Salmon is-a Fish
class Salmon(Fish):
    pass


## Halibut is-a Fish
class Halibut(Fish):
    pass


## rover is-a Dog
rover = Dog("Rover")

## satan is-a Cat
satan = Cat("Satan")

## mary is-a Person
mary = Person("Mary")

## mary's pet is satan
mary.pet = satan
print(mary.pet.name)

## frank is-a Employee
frank = Employee("Frank", 120000)

## frank's pet is rover
frank.pet = rover
print(frank.name)
print(frank.pet.name)
print(frank.salary)
## flipper is-a Fish
flipper = Fish()

## crouse is-a Salmon
crouse = Salmon()

## harry is-a Halibut
harry = Halibut()