The indentation here is all a little weird. Looks like it should all be indented 2 spaces. The last line here has the trailing comma in an odd place. It should be:
```
  'changed' => array(
    'data' => t('Updated'),
    'field' => 'n.changed',
    'sort' => 'desc',
    'class' => array(RESPONSIVE_PRIORITY_LOW),
  ),
```