title: Python Pickle Dump 'Wb' parameter
body: <p>In examples of using pickle to save data, I often encounter a second parameter where many people use <code>'wb'</code>, for instance: </p>
  
  <p><code>pickle.dump(obj, open('save.p', 'wb'))</code>. </p>
  
  <p>What does the <code>'wb'</code> parameter do? </p>