title: Python: Disable http_proxy in urllib2
body: <p>I am using a proxy set as an environment variable (export http_proxy=example.com).  For one call using urllib2 I need to temporarily disable this, ie. unset the http_proxy.  I have tried various methods suggested in the documentation and interwebs, but so far have been unable to unset the proxy.  So far I have tried:</p>
  
  <pre><code># doesn't work
  req = urllib2.Request('http://www.google.com')
  req.set_proxy(None,None)
  urllib2.urlopen(req)
  
  # also doesn't work
  urllib.getproxies = lambda x = None: {}
  </code></pre>