// function to delete all labels
  function deleteAllLabels() {
      var sheet = SpreadsheetApp.openById(SSID).getSheetByName('Labels');   sheet.clear();
      var response =
      Gmail.Users.Labels.list('me');
       for (var i = 0; i < response.labels.length; i++) {
    var label = response.labels[i];
           if (label.type == 'user')      {
      Gmail.Users.Labels.remove('me', label.id);        sheet.appendRow([i, "deleted", label.name, label.id]);
      }
   }
 }