title: Python and Round Milliseconds in Datetime Object
body: <p>Everywhere I look seems to do some sort of truncation on milliseconds after converting a datetime object to a string and then manipulating the string.  I would like to round the milliseconds within a datetime object without converting it to a string - is this possible?  For example, I have</p>
  
  <pre><code>datetime.datetime(2018, 2, 20, 14, 25, 43, 215000)
  </code></pre>
  
  <p>I would like this to be:</p>
  
  <pre><code>datetime.datetime(2018, 2, 20, 14, 25, 43, 200000)
  </code></pre>
  
  <p>I would also like this to be rounded appropriately meaning that if it was 249999 it would round downward to 200000 and if 250000 it would round upward to 300000.  Help?</p>