Missing e in function - Tutorial #1110

<script>
  var tabs = document.querySelector('paper-tabs');
  tabs.addEventListener('core-select', function() {
    console.log("Selected: " + tabs.selected);
  });
</script>
</body>

<script>
    var tabs = document.querySelector('paper-tabs');
    tabs.addEventListener('core-select', function(e) {
      console.log("Selected: " + tabs.selected);
    });
</script>
</body>