title: need the average from a list of timedelta objects
body: <p>I have created a list of <code>timedelta</code> objects and i need to get the average of this list. when i try to do </p>
  
  <pre><code>return (sum(delta_list)/(len(delta_list)-1))
  </code></pre>
  
  <p>i get </p>
  
  <pre><code>TypeError: unsupported operand type(s) for +: 'int' and 'datetime.timedelta'
  </code></pre>
  
  <p>I am new at working with python's <code>datetime</code> classes. I also would like to know how to get this average into a format like days: hours: mins: i don't need anything smaller than mins.</p>