title: Catching ValueError: unknown url type: urllib2 Python
body: <p>I'm getting the following exception when I enter an invalid URL: <code>ValueError: unknown url type: blob</code></p>
  
  <p>I'm trying to catch this error with the following code but it's not working:</p>
  
  <pre><code>try:
      req = urllib2.Request(url)
      conn =  urllib2.urlopen(req)
      content = conn.read()
  except urllib2.URLError, e:
      print 'Error: Invalid URL'
  </code></pre>