python爬虫 为何for循环语句无法输出

Question

请问下面这段代码，输出时只显示第一排中文标题，然后就停止了，本人小白，，刚学，很多不懂，大虾求解

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import urllib2
import re
from bs4 import BeautifulSoup

def crawl(url):
    page = urllib2.urlopen(url)
    contents = page.read()
    soup = BeautifulSoup(contents)
    print(u' 豆瓣电影TOP250:\n 序号 \t影片名\t 评分 \t评价人数 \t 链接 ')
    for tag in soup.find_all('tr', class_='item'):
    #print tag
        m_order = int(tag.find('td', class_='m_order').get_text())
        m_name = tag.a.get_text()
        m_year = tag.span.get_text()
        m_rating_score = float(tag.em.get_text())
        m_rating_num = int(tag.find(headers="m_rating_num").get_text())
        m_url=str(tag.find('a')).split('"')[1]
        #print m_url

       print("%s %s %s %s %s %s " % (m_order, m_name, m_year, m_rating_score, m_rating_num,m_url)) 
if name == 'main':
crawl('http://movie.douban.com/top250?format=text')