title: prefix notation parsing in python
body: <p>Right off the bat - no, this is NOT homework.</p>
  
  <p>I would like to write a prefix notation parser in python (for sums presently)... for example</p>
  
  <p>if given: <code>+ 2 2</code> it would return: <code>4</code></p>
  
  <p>ideas?</p>