@classmethod
    def create(cls, entry):
        try:
            # If import_module succeeds, entry is a path to an app module,
            # which may specify an app config class with default_app_config.
            # Otherwise, entry is a path to an app config class or an error.
            module = import_module(entry)

        except ImportError:
            # Track that importing as an app module failed. If importing as an
            # app config class fails too, we'll trigger the ImportError again.
            module = None

            mod_path, _, cls_name = entry.rpartition('.')

            # Raise the original exception when entry cannot be a path to an
            # app config class.
            if not mod_path:
                raise

        else:
            try:
                # If this works, the app module specifies an app config class.
                entry = module.default_app_config
            except AttributeError:
                # Otherwise, it simply uses the default app config class.
                return cls(entry, module)
            else:
                mod_path, _, cls_name = entry.rpartition('.')

        # If we're reaching this point, we must attempt to load the app config
        # class located at <mod_path>.<cls_name>
        mod = import_module(mod_path)
        try:
            cls = getattr(mod, cls_name)
        except AttributeError:
            if module is None:
                # If importing as an app module failed, that error probably
                # contains the most informative traceback. Trigger it again.
                import_module(entry)
            else:
                raise

        # Check for obvious errors. (This check prevents duck typing, but
        # it could be removed if it became a problem in practice.)
        if not issubclass(cls, AppConfig):
            raise ImproperlyConfigured(
                "'%s' isn't a subclass of AppConfig." % entry)

        # Obtain app name here rather than in AppClass.__init__ to keep
        # all error checking for entries in INSTALLED_APPS in one place.
        try:
            app_name = cls.name
        except AttributeError:
            raise ImproperlyConfigured(
                "'%s' must supply a name attribute." % entry)

        # Ensure app_name points to a valid module.
        app_module = import_module(app_name)

        # Entry is a path to an app config class.
        return cls(app_name, app_module)
Factory that creates an app config from an entry in INSTALLED_APPS.
dataset/ETHPy150Open django/django/django/apps/config.py/AppConfig.create