function save_Gmail_as_PDF(){
  var label = GmailApp.getUserLabelByName("Salva come PDF");  
  if(label == null){
    GmailApp.createLabel('Salva come PDF');
  }
  else{
    var threads = label.getThreads();  
    for (var i = 0; i < threads.length; i++) {  
      var messages = threads[i].getMessages();  
      var message = messages[0];
      var body    = message.getBody();
      var subject = message.getSubject();
      var attachments  = message.getAttachments();
      for(var j = 1;j<messages.length;j++){
        body += messages[j].getBody();
        var temp_attach = messages[j].getAttachments();
        if(temp_attach.length>0){
          for(var k =0;k<temp_attach.length;k++){
            attachments.push(temp_attach[k]);
          }
        }
      } 
      // Crea un file HTML a partire dal contenuto del messaggio di posta elettronica
      var bodydochtml = DocsList.createFile(subject+'.html', body, "text/html")
      var bodyId=bodydochtml.getId();
 
      // Converti codice HTML in PDF
      var bodydocpdf = bodydochtml.getAs('application/pdf');
      if(attachments.length > 0){
        DocsList.createFolder(subject);
        var folder = DocsList.getFolder(subject);
        for (var j = 0; j < attachments.length; j++) {
          folder.createFile(attachments[j].getName(),attachments[j].getBytes());
        }
        folder.createFile(bodydocpdf);
      }
      else{
        DocsList.createFile(bodydocpdf);
      }      
      DocsList.getFileById(bodyId).setTrashed(true);
      label.removeFromThread(threads[i]);
    }
  }  
}