def METHOD_NAME(self, app_config: CFG) -> None:
    # INFO - G.M - 2019-02-01 - check if template are available,
    # do not allow running with email_notification_activated
    # if templates needed are not available
    if app_config.EMAIL__NOTIFICATION__ACTIVATED:
        templates = {
            "upload_permission_to_emitter": app_config.EMAIL__NOTIFICATION__UPLOAD_PERMISSION_TO_EMITTER__TEMPLATE__HTML,
            "upload_permission_to_receiver": app_config.EMAIL__NOTIFICATION__UPLOAD_PERMISSION_TO_RECEIVER__TEMPLATE__HTML,
            "new_upload_event": app_config.EMAIL__NOTIFICATION__NEW_UPLOAD_EVENT__TEMPLATE__HTML,
        }
        for template_description, template_path in templates.items():
            if not template_path or not os.path.isfile(template_path):
                raise ConfigurationError(
                    "ERROR: email template for {template_description} "
                    'not found at "{template_path}".'.format(
                        template_description=template_description,
                        template_path=template_path,
                    )
                )