class Dog:
    def __init__(self, name, greeting):
        self.name = name
        self.breed = breed
        self.greeting = greeting

    def bark(self):
        print("'{}!' says the goodest boi, {}.".format(self.greeting, self.name))

    def sit(self):
        print("{} sits".format(self.name))

    def roll(self):
        print("{} rolls over".format(self.name))

    
