import concurrent.futuresimport urllib.request
URLS = ['http://www.foxnews.com/',        'http://www.cnn.com/',        'http://europe.wsj.com/',        'http://www.bbc.co.uk/',        'http://nonexistent-subdomain.python.org/']

# Retrieve a single page and report the URL and contentsdef load_url(url, timeout):    with urllib.request.urlopen(url, timeout=timeout) as conn:        return conn.read()

# We can use a with statement to ensure threads are cleaned up promptlywith concurrent.futures.ThreadPoolExecutor(max_workers=5) as executor:    # Start the load operations and mark each future with its URL    future_to_url = {executor.submit(load_url, url, 60): url for url in URLS}    for future in concurrent.futures.as_completed(future_to_url):        url = future_to_url[future]        try:            data = future.result()        except Exception as exc:            print('%r generated an exception: %s' % (url, exc))        else:            print('%r page is %d bytes' % (url, len(data)))