title: Call to a member function add() on a non-object when trying to add to DateTime
body: <p>I had a question on this previously and it was answered and worked, but now I am getting the same error with some different codes and I'm attempting a different outcome.</p>
  
  <p>I am trying to add 1 minute 30 seconds to the current DateTime stamp:</p>
  
  <p>my code is:</p>
  
  <pre><code>&lt;?php
  ini_set("display_errors", 1); error_reporting(E_ALL); 
  date_default_timezone_set('America/Denver');
  echo $date = (new DateTime())-&gt;format('Y-m-d H:i:s'); //This echos the correct DateTime in SQL format so I can UPDATE and SELECT easily
  echo $datestuff = $date-&gt;add(new DateInterval("PT1H"))-&gt;format('Y-m-d H:i:s'); //This is where the error is when attempting to add 1 hour
  ?&gt;
  </code></pre>
  
  <p>question -</p>
  
  <p>How would I add 1.5 minutes to $date and end up with the same format?</p>
  
  <p>Thanks!</p>