def item_completed(self, results, item, info):
        """Called per item when all media requests has been processed"""
        if self.LOG_FAILED_RESULTS:
            for ok, value in results:
                if not ok:
                    logger.error(
                        '%(class)s found errors processing %(item)s',
                        {'class': self.__class__.__name__, 'item': item},
                        exc_info=failure_to_exc_info(value),
                        extra={'spider': info.spider}
                    )
        return item
Called per item when all media requests has been processed
stackoverflow/venv/lib/python3.6/site-packages/scrapy/pipelines/media.py