title: Python: convert date from string to number
body: <p>how I have a simple question. I need to convert a date in string format to a number:</p>
  
  <pre><code>time = '2014-03-05 07:22:26.976637+00:00'
  type(time)
        str
  </code></pre>
  
  <p>I would like to convert this date to a unique number</p>
  
  <p>Thank you.</p>