import url_manager,html_downloader,html_parser,\
     html_outputer

class SpiderMain(object):
    def _inti_(self):
        self.urls = url_manager.UrlManager()
        self.downloader = html_downloader.HtmlDdownloader()
        self.parser = html_parser.HtmlParser()
        self.outputer = html_outputer.HtmlOutputer()

    def craw(self,root_url):
        count = 1
        self.urls.add_new_url(root_url)
        while self.urls.has_new_url():
            try:
                new_url = self.url.get_new_url()
                print 'craw %d : %s'%(count,new_url)
                html_cont = self.downloader.download(new_url)
                new_urls,new_data = self.parser.parse(new_url,html_cont)
                self.urls.add_new_urls(new_urls)
                self.outputer.collect_data(new_data)

                if count == 1000:
                    break

                count = count+1
            except:
                print 'craw failed'
             
        self.outputer.output_html()

         




if _name_=="_main_":
    root_url = "http://baike.baidu.com/view/21087.htm"
    obj_spider = SpiderMain()
    obj_spider.craw(root_url)

显示_name_未定义，请问应该如何解决？

IDLE, python 2.7.6