title: addViewer the method used with the class DriveApp always sends the email to the recipient. Can I disable the email?
body: <p>Code A and B do the same things but in case A when add a viewer, the command addViewer don't send the email to currentUser. Instead, in the case B when add a viewer the currentUser receive an email of file sharing.</p>
  
  <pre><code>//CASE A
  var f = DocsList.getFolderById(folder.getId());  
  f.addViewer(currentUser);
  
  //CASE B
  var f = DriveApp.getFolderById(folder.getId());
  f.addViewer(currentUser);
  </code></pre>
  
  <p>I would like to share wihouth automatic email because at the end of procedure I'll send a custom email (with the file inside folder link) if the procedure completed successfull, otherwaise I will delete the folder.
  How can I do? DocList will soon be deprecated!! </p>