class Dog:
    def __init__(self,name):
        self.name = name
        self.tricks = []
        return

    def add_trick(self,trick):
        self.tricks.append(trick)
        return

    def show_tricks(self):
        print(self.name+"'s tricks are:")
        for x in self.tricks:
            print(x)

d = Dog('Tony')
d.add_trick('sprint')
d.add_trick('sleep')
d.name = 'Tony2'
d.show_tricks()

e = Dog('Princess')
e.add_trick('sit')
e.add_trick('roll over')
e.eye_color = 'Brown'
e.show_tricks()