title: python urllib usage
body: <p>I imported two libraries <code>urllib</code> and <code>from urllib.request import urlopen</code>.</p>
  
  <p>The second  one is contained  in the first</p>
  
  <p>When I went over the code and tried to remove the <code>from urllib.request import urlopen</code> line , I got this message:</p>
  
  <pre><code>opnerHTMLnum = urllib.request.build_opener()
  AttributeError: 'module' object has no attribute 'request'
  </code></pre>
  
  <p>When I restore the <code>from urllib.request import urlopen</code> line the code runs .</p>
  
  <p>Can anyone explain why?</p>
  
  <pre><code>import re
  #import http.cookiejar
  import os.path
  #import time
  #import urllib3
  import urllib
  from urllib.request import urlopen
  import sys
  import smtplib
  from email.mime.text import MIMEText
  
  # ...
  
      opnerHTMLnum = urllib.request.build_opener()
  </code></pre>