Using Python to Access Web Data_Coursera_Notes_Ch13_WebServices_BeautifulSoup

[fairypp]

import urllib
from bs4 import BeautifulSoup
#from BeautifulSoup import *

url = raw_input('Enter - ')

html = urllib.urlopen(url).read()
soup = BeautifulSoup(html)

# Retrieve a list of the anchor tags
# Each tag is like a dictionary of HTML attributes

tags = soup('a')

for tag in tags:
    print tag.get('href', None)

[sheersh2001]

i am getting this trace back. can you help me out.