第十四章from_crawler越界

[mapisland]

from_crawler()函数按照书上打的 但是却运行不出来
错误的提示如下：
2018-07-28 20:01:04 [twisted] CRITICAL: Unhandled error in Deferred:
2018-07-28 20:01:04 [twisted] CRITICAL:
Traceback (most recent call last):
File "e:\python\lib\site-packages\twisted\internet\defer.py", line 1418, in _inlineCallbacks
result = g.send(result)
File "e:\python\lib\site-packages\scrapy\crawler.py", line 98, in crawl
six.reraise(*exc_info)
File "e:\python\lib\site-packages\scrapy\crawler.py", line 80, in crawl
self.engine = self._create_engine()
File "e:\python\lib\site-packages\scrapy\crawler.py", line 105, in _create_engine
return ExecutionEngine(self, lambda _: self.stop())
File "e:\python\lib\site-packages\scrapy\core\engine.py", line 70, in init
self.scraper = Scraper(crawler)
File "e:\python\lib\site-packages\scrapy\core\scraper.py", line 71, in init
self.itemproc = itemproc_cls.from_crawler(crawler)
File "e:\python\lib\site-packages\scrapy\middleware.py", line 58, in from_crawler
return cls.from_settings(crawler.settings, crawler)
File "e:\python\lib\site-packages\scrapy\middleware.py", line 36, in from_settings
mw = mwcls.from_crawler(crawler)
TypeError: unbound method from_crawler() must be called with ZhihucrawlPipeline instance as first argument (got Crawler instance instead)