disappearing_descriptor.py

class Person:
    def __init__(self, owner=None):
        self.owner = owner

    def __set_name__(self, _, name):
        self.name = name

    def __get__(self, inst, _):
        if self.owner is None:
            print("Binding person to world")
            value = Person(inst)
            inst.__dict__[self.name] = value
        else:
            value = self
        return value

    def hello(self):
        return f"Hello {self.owner}!"

class World(object):
    meep = Person()
    
    def __str__(self):
        return "World"

if __name__ == "__main__":
    obj = World()
    print(obj.meep.hello())
    print(obj.meep.hello())