title: display time series in ms in python
body: <p>I have posix times, e.g. 1572015698537 and want to convert into a human readable string format. I tried</p>
  
  <pre><code>import datetime
  
  s = 1572015698537 / 1000.0
  
  print(datetime.datetime.fromtimestamp(s).strftime('%Y-%m-%d %H:%M:%S.%f'))
  </code></pre>
  
  <p>but this just displays</p>
  
  <pre><code>2019-10-25 17:01:38.000000
  </code></pre>
  
  <p>and hides the milliseconds. Can someone help?</p>