title: Python: KeyError/IOError with urllib.urlopen
body: <p>I am trying to pass some text to this <a href="http://ipeirotis.appspot.com/readability-api.html" rel="nofollow">readability API</a> like so:</p>
  
  <pre><code>text = 'this reminds me of the Dutch 2001a caravan full of smoky people Auld Lang Syne'
  # construct Readability Metrics API url
  request_url = 'http://ipeirotis.appspot.com/readability/GetReadabilityScores?format=json&amp;text=%s' % text
  request_url = urllib.quote_plus(request_url.encode('utf-8'))
  # make request
  j = json.load(urllib.urlopen(request_url))
  </code></pre>
  
  <p>I get this error on the last line though:</p>
  
  <blockquote>
    <p>[Errno 2] No such file or directory: 'http://ipeirotis.appspot.com/readability/GetReadabilityScores?format=json&amp;text=this+reminds+me+of+the+Dutch+2001a+caravan+full+of+smoky+people+Auld+Lang+Syne'</p>
  </blockquote>
  
  <p>However, the URL in the error is valid and returns a response when you visit it. How do I encode the URL so that I can use urlopen? Thanks a lot.</p>