title: Subtract two dates to give a timedelta
body: <p>I'm trying to get a value from one of my database values, which will be given by subtracting the purchase date from today's date.  I've written my code this way:</p>
  
  <pre><code>delta = datetime.now() - item.purchase_date
  </code></pre>
  
  <p>But this gives me this error:</p>
  
  <pre><code>unsupported operand type(s) for -: 'datetime.datetime' and 'datetime.date'
  </code></pre>
  
  <p>If I use <code>datetime.datetime.now()</code> this doesn't work.  What am I missing.  Thanks.</p>