问题描述：

解决Unhandled error in Deferred或提示NameError: name 'xxPipeline' is not defined，错误描述如下：

[root@Uu tutu]# scrapy crawl tutu
2018-08-26 18:18:12 [scrapy.utils.log] INFO: Scrapy 1.5.1 started (bot: tutu)
2018-08-26 18:18:12 [scrapy.utils.log] INFO: Versions: lxml 3.2.1.0, libxml2 2.9.1, cssselect 1.0.3, parsel 1.5.0, w3lib 1.19.0, Twisted 18.7.0, Python 2.7.5 (default, Jul 13 2018, 13:06:57) - [GCC 4.8.5 20150623 (Red Hat 4.8.5-28)], pyOpenSSL 18.0.0 (OpenSSL 1.1.0i  14 Aug 2018), cryptography 2.3.1, Platform Linux-3.10.0-693.el7.x86_64-x86_64-with-centos-7.4.1708-Core
2018-08-26 18:18:12 [scrapy.crawler] INFO: Overridden settings: {'NEWSPIDER_MODULE': 'tutu.spiders', 'CONCURRENT_REQUESTS': 1, 'SPIDER_MODULES': ['tutu.spiders'], 'BOT_NAME': 'tutu', 'COOKIES_ENABLED': False, 'USER_AGENT': 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; AcooBrowser; .NET CLR 1.1.4322; .NET CLR 2.0.50727)', 'DOWNLOAD_DELAY': 5}
2018-08-26 18:18:12 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.memusage.MemoryUsage',
 'scrapy.extensions.logstats.LogStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.corestats.CoreStats']
2018-08-26 18:18:13 [scrapy.middleware] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
 'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
 'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
 'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
 'scrapy.downloadermiddlewares.retry.RetryMiddleware',
 'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
 'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
 'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
 'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware',
 'scrapy.downloadermiddlewares.stats.DownloaderStats']
2018-08-26 18:18:13 [scrapy.middleware] INFO: Enabled spider middlewares:
['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
 'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
 'scrapy.spidermiddlewares.referer.RefererMiddleware',
 'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
 'scrapy.spidermiddlewares.depth.DepthMiddleware']
Unhandled error in Deferred:
2018-08-26 18:18:13 [twisted] CRITICAL: Unhandled error in Deferred:

2018-08-26 18:18:13 [twisted] CRITICAL: 
Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/twisted/internet/defer.py", line 1418, in _inlineCallbacks
    result = g.send(result)
  File "/usr/lib64/python2.7/site-packages/scrapy/crawler.py", line 98, in crawl
    six.reraise(*exc_info)
  File "/usr/lib64/python2.7/site-packages/scrapy/crawler.py", line 80, in crawl
    self.engine = self._create_engine()
  File "/usr/lib64/python2.7/site-packages/scrapy/crawler.py", line 105, in _create_engine
    return ExecutionEngine(self, lambda _: self.stop())
  File "/usr/lib64/python2.7/site-packages/scrapy/core/engine.py", line 70, in __init__
    self.scraper = Scraper(crawler)
  File "/usr/lib64/python2.7/site-packages/scrapy/core/scraper.py", line 71, in __init__
    self.itemproc = itemproc_cls.from_crawler(crawler)
  File "/usr/lib64/python2.7/site-packages/scrapy/middleware.py", line 58, in from_crawler
    return cls.from_settings(crawler.settings, crawler)
  File "/usr/lib64/python2.7/site-packages/scrapy/middleware.py", line 34, in from_settings
    mwcls = load_object(clspath)
  File "/usr/lib64/python2.7/site-packages/scrapy/utils/misc.py", line 44, in load_object
    mod = import_module(module)
  File "/usr/lib64/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/home/BS/scrapy/tutu/tutu/pipelines.py", line 9, in <module>
    class TutuPipeline(ImagesPipeline):
NameError: name 'ImagesPipeline' is not defined

解决过程：

 根据错误信息提示，发现是pipelines.py文件中的ImagesPipeline的定义问题，

后经反复实验，发现将class TutuPipeline(ImagesPipeline) 中的类换成object即不报错，

所以，解决方案为：将class TutuPipeline(ImagesPipeline) 中的类ImagesPipeline换成object即可。