Closure black magic

gistfile1.py

for x in entrySelectors:
	datetext = x.select('.//pubDate/text()').extract()
	datetext = u'0000-00-00 00:00:00+00:00' if len(datetext)<1 else dateutil.parser.parse(datetext[0])
	templist = x.select('.//link["nytimes.com/"]/text()').extract()
	
	if len(templist)>0 :
		def cb(tx):
			return lambda r: self.check_call(r, tx)
		links.append(templist[0])
		#tx = str(copy.deepcopy(datetext))
		newitem = Request(templist[0], callback=cb(datetext))
		itemlist.append( newitem)