title: Why does python return an error when using urllib.request.urlopen for certain websites
body: <p>when I use url lib.requests in python 3, it works for some websites but for others it returns an error:</p>
  
  <pre><code>import urllib.request
  urllib.request.urlopen('wikipedia.org')
  
  Traceback (most recent call last):
    File "/Users/etudiant/Desktop/test.py", line 3, in &lt;module&gt;
      urllib.request.urlopen('wikipedia.org')
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 222, in urlopen
      return opener.open(url, data, timeout)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 510, in open
      req = Request(fullurl, data)
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 328, in __init__
      self.full_url = url
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 354, in full_url
      self._parse()
    File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 383, in _parse
      raise ValueError("unknown url type: %r" % self.full_url)
  ValueError: unknown url type: 'wikipedia.org'
  &gt;&gt;&gt; 
  </code></pre>