class GreetingClass:
    name = "user"

    def say_hello(self):
        """Class method."""
        return "Hello " + self.name

    def say_goodbye(self):
        """Class method."""
        return "Goodbye " + self.name


greeter = GreetingClass()

print(greeter.say_hello())
print(greeter.say_goodbye())
assert greeter.say_hello() == "Hello user"
assert greeter.say_goodbye() == "Goodbye user"