title: How do I convert the output of "getctime()" and "getmtime()" into the time format required by HTML's "published_time" and "modified_time" META tags?
body: <p>My website's articles are written using <code>.md</code> files, to get the created and modified times of these files I use the <code>os.path.getctime()</code> and <code>os.path.getmtime()</code> methods.</p>
  
  <p>The output of these methods look like this:</p>
  
  <ul>
  <li><code>1553541590.723329</code></li>
  <li><code>1553541590.723329</code></li>
  </ul>
  
  <p>While HTML requires this format:</p>
  
  <ul>
  <li><code>2001-09-17T05:59:00+01:00</code></li>
  <li><code>2013-09-16T19:08:47+01:00</code></li>
  </ul>
  
  <p>I have two questions regarding this matter:</p>
  
  <ol>
  <li>What's are the names of these two time formats?</li>
  <li>How do I change the output of those methods to look like the required HTML format?</li>
  </ol>
  
  <p>Thanks.</p>