/**
 * Implements hook_field_attach_delete_bundle().
 */
function {{ machine_name }}_field_attach_delete_bundle($entity_type, $bundle, $instances) {
  // Remove the extra weights variable information for this bundle.
  $extra_weights = variable_get('field_extra_weights', array());
  if (isset($extra_weights[$entity_type][$bundle])) {
    unset($extra_weights[$entity_type][$bundle]);
    variable_set('field_extra_weights', $extra_weights);
  }
}