boromir674 / so-magic

        return self._state

class DataManagerCommandFactory(AbstractCommandFactory, ABC):

    subclasses = {}

    @classmethod

    def register_as_subclass(cls, factory_type):

        def wrapper(subclass):

            cls.subclasses[factory_type] = subclass

            return subclass

        return wrapper

    @classmethod

    def create(cls, factory_type, *args, **kwargs):

        if factory_type not in cls.subclasses:

            raise ValueError('Bad "Factory type" \'{}\''.format(factory_type))

        return cls.subclasses[factory_type](*args, **kwargs)

@DataManagerCommandFactory.register_as_subclass('select_variables')

    def construct(self, *args, **kwargs) -> Command:

        raise NotImplementedError

class BaseCommandFactory(AbstractCommandFactory, ABC):

    subclasses = {}

    @classmethod

    def register_as_subclass(cls, factory_type):

        def wrapper(subclass):

            cls.subclasses[factory_type] = subclass

            return subclass

        return wrapper

    @classmethod

    def create(cls, factory_type, *args, **kwargs):

        if factory_type not in cls.subclasses:

            raise ValueError('Bad "Factory type" \'{}\''.format(factory_type))

        return cls.subclasses[factory_type](*args, **kwargs)

@BaseCommandFactory.register_as_subclass('generic')