我在spider类中有一个列表。我需要初始化它。代码如下所示：

class Myspider(SitemapSpider):
    name = 'spidername'

    sitemap_urls = [
                    'https://www.arabam.com/sitemap/otomobil_13.xml']
sitemap_rules = [
    ('/otomobil/', 'parse'),

]
custom_settings = {'FEED_FORMAT':'csv','FEED_URI': "arabam_"+str(datetime.today().strftime('%d%m%y'))+'.csv'
                   }
crawled = []
new_links = 0
def parse(self,response):
    if self.new_links >3:
        with open("URLs", "wb") as f:

                pickle.dump(self.crawled, f)
        self.new_links = 0
    for td in response.xpath("/html/body/div[3]/div[6]/div[4]/div/div[2]/table/tbody/tr/td[4]/div/a"):

        if link[0] not in self.crawled:

            self.crawled.append(link[0])

################################某些代码

process = CrawlerProcess({
})
Myspider.crawled = []
Myspider.crawled.append("hi")
try:
        with (open("URLs", "rb")) as openfile:
            while True:
                try:
                    Myspider.crawled = pickle.load(openfile)

                except EOFError:
                    break
except:
        with open("URLs", "wb") as f:
            pickle.dump("", f)
print(Myspider.crawled)
process.crawl(Myspider, Myspider.crawled)
process.start() # the script wi

它不断抛出以下异常：

Traceback (most recent call last):
  File "C:\Users\fatima.arshad\AppData\Local\Continuum\anaconda2\envs\web_scraping\lib\site-packages\twisted\internet\defer.py", line 151, in maybeDeferred
    result = f(*args,**kw)
  File "C:\Users\fatima.arshad\AppData\Local\Continuum\anaconda2\envs\web_scraping\lib\site-packages\pydispatch\robustapply.py", line 55, in robustApply
    return receiver(*arguments,**named)
  File "C:\Users\fatima.arshad\AppData\Local\Continuum\anaconda2\envs\web_scraping\lib\site-packages\scrapy\extensions\feedexport.py", line 262, in item_scraped
    slot = self.slot
AttributeError: 'FeedExporter' object has no attribute 'slot'

根据一些资源，这是因为：

Traceback (most recent call last):
  File "C:\Users\fatima.arshad\AppData\Local\Continuum\anaconda2\envs\web_scraping\lib\site-packages\twisted\internet\defer.py", line 151, in maybeDeferred
    result = f(*args,**kw)
  File "C:\Users\fatima.arshad\AppData\Local\Continuum\anaconda2\envs\web_scraping\lib\site-packages\pydispatch\robustapply.py", line 55, in robustApply
    return receiver(*arguments,**named)
  File "C:\Users\fatima.arshad\AppData\Local\Continuum\anaconda2\envs\web_scraping\lib\site-packages\scrapy\extensions\feedexport.py", line 232, in open_spider
    uri = self.urifmt % self._get_uri_params(spider)
  File "C:\Users\fatima.arshad\AppData\Local\Continuum\anaconda2\envs\web_scraping\lib\site-packages\scrapy\extensions\feedexport.py", line 313, in _get_uri_params
    params[k] = getattr(spider, k)
  File "C:\Users\fatima.arshad\AppData\Local\Continuum\anaconda2\envs\web_scraping\lib\site-packages\scrapy\spiders\__init__.py", line 36, in logger
    logger = logging.getLogger(self.name)
  File "C:\Users\fatima.arshad\AppData\Local\Continuum\anaconda2\envs\web_scraping\lib\logging\__init__.py", line 1845, in getLogger
    return Logger.manager.getLogger(name)
  File "C:\Users\fatima.arshad\AppData\Local\Continuum\anaconda2\envs\web_scraping\lib\logging\__init__.py", line 1174, in getLogger
    raise TypeError('A logger name must be a string')
TypeError: A logger name must be a string

我该如何传递列表给它呢？或者有什么方法可以让这个列表只被scrapy spider初始化一次？列表包含了所有已经爬过的url。这个列表是pickle的。当代码开始时，它初始化这个列表，并且只有当链接不在这个列表中时才进一步爬网。