Changed has_app to return a boolean.

    def has_app(self, app_name):

        """

        Returns the application config if one is registered and None otherwise.

        Checks whether an application with this name exists in the app cache.

        app_name is the full name of the app eg. 'django.contrib.admin'.

        It's safe to call this method at import time, even while the app cache

        is being populated. It returns None for apps that aren't loaded yet.

        """

        app_config = self.app_configs.get(app_name.rpartition(".")[2])

        if app_config is not None and app_config.name != app_name:

            app_config = None

        return app_config

        return app_config is not None and app_config.name == app_name:

    def has_model(self, app_label, model_name):

        """