import sys

PY3K = sys.version_info >= (3, 0)
if not PY3K:
  import urllib
else:
  import urllib.request as urllib

def callback(blocks, block_size, total_size):
  print(blocks, block_size, total_size)


url = 'http://docs.python.org/2/library/urllib.html'
urllib.urlretrieve(url, 'urlparse.html', callback)