scrapy+mongoDB小问题

遇到错误

Traceback (most recent call last):
  File "e:\python\lib\site-packages\twisted\internet\defer.py", line 1386, in _inlineCallbacks
    result = g.send(result)
  File "e:\python\lib\site-packages\scrapy\crawler.py", line 82, in crawl
    yield self.engine.open_spider(self.spider, start_requests)
TypeError: name must be an instance of str

解决方法

pipelines.py
mongo_db=crawler.settings.get('MONGO_DATABASE','items'))

ps：纯属手贱，，找了一下午