title: six 1.4.1 is installed but six>=1.5.2 is required by set(['OpenSSL']) in mac OS sierra
body: <p>I am trying to install Twilio using <code>sudo pip install twilio</code> but it fails with below error logs:</p>
  
  <pre><code>Processing dependencies for twilio
  error: six 1.4.1 is installed but six&gt;=1.5.2 is required by set(['pyOpenSSL'])
  </code></pre>
  
  <p>I also tried <code>sudo easy_install twilio</code>.</p>
  
  <p>Is it OS restriction?
  I am first time using python.</p>