passing arguments to scrapy -

i followed advice these 2 posts trying create generic scrapy spider:

how pass user defined argument in scrapy spider

creating generic scrapy spider

but i'm getting error variable supposed passing argument not defined. missing in init method?

code:

from scrapy.spider import basespider scrapy.selector import htmlxpathselector  data.items import dataitem  class companyspider(basespider):     name = "woz"      def __init__(self, domains=""):         '''         domains string         '''         self.domains = domains      deny_domains = [""]     start_urls = [domains]      def parse(self, response):         hxs = htmlxpathselector(response)         sites = hxs.select('/html')         items = []         site in sites:             item = dataitem()             item['text'] = site.select('text()').extract()             items.append(item)         return items 

here command-line:

scrapy crawl woz -a domains="http://www.dmoz.org/computers/programming/languages/python/books/" 

and here error:

nameerror: name 'domains' not defined 

you should call super(companyspider, self).__init__(*args, **kwargs) @ beginning of __init__.

def __init__(self, domains="", *args, **kwargs):     super(companyspider, self).__init__(*args, **kwargs)     self.domains = domains 

in case first requests depend on spider argument, override start_requests() method, without overriding __init__(). parameter name command line aleady available attribute spider:

class companyspider(basespider):     name = "woz"     deny_domains = [""]      def start_requests(self):         yield request(self.domains) # example if domains single url      def parse(self, response):         ...