Tomáš Kuzma

class World:
    
    def greet(self):
        print('Hello, world!')


world = World()
world.greet()

class Person:
    
    def __init__(self, fullname):
        self.first, self.last = fullname.split()

    def greet(self):
        print('Hello, {}!'.format(self.first))

    def print(self):
        print('{0.last}, {0.first}'.format(self))


john = Person('John Smith')
john.greet()
john.print()