title: Obtaining total and free used space via Google App Script
body: <p>I discover just today that <a href="https://developers.google.com/apps-script/reference/drive/drive-app#getStorageUsed%28%29" rel="nofollow noreferrer"><code>DriveApp#getStorageUsed()</code></a> is referring ONLY to Google Drive.</p>
  
  <p>I didn't expect this behaviour because <code>getStorageLimit</code> is intended as global. in fact, says 15 GB for my free account.</p>
  
  <p>I don't understand how to get the amout of used storage OR totally OR divided by services. </p>
  
  <p>My problem is that I've a lot of photos on Google Photos and these are not summed as storage space used.</p>
  
  <p>Is there a way to get OR the sum of used space OR used space by service (via single api call or via  a set of api calls) ?</p>