example.py

my_thing = SomeThingModel()


# type 1
class ModifyThing:

    @classmethod
    def format_date(cls, thing):
        return thing.created.format('MMMM ddd ...')

    @classmethod
    def format_thing(cls, thing):
        return f'Thing {thing.id}, created {cls.format_date(thing)}'

    @classmethod
    def modify_thing(cls, thing):
        print('Modifying', cls.format_thing(thing))

        thing.field = 'new-value'
        thing.save()

    @classmethod
    def process(cls, thing):
        cls.modify_thing(thing)


ModifyThing.process(my_thing)


# type 2
class ModifyThing:

    def __init__(self, thing):
        self.thing = thing

    def format_date(self):
        return self.thing.created.format('MMMM ddd ...')

    def format_thing(self):
        return f'Thing {self.thing.id}, created {self.format_date()}'

    def modify_thing(self):
        print('Modifying', self.format_thing())

        self.thing.field = 'new-value'
        self.thing.save()

    def process(self):
        self.modify_thing()


ModifyThing(my_thing).process()