Drupal → Переместить поле E-mail в существующий checkout pane

Пример перемещения поля E-mail в checkout pane commerce_fieldgroup_pane__group_customer созданный с помощью Commerce Fieldgroup Panes

/**
 * Implements hook_form_FORM_ID_alter(): commerce_checkout_form_checkout.
 */
function MODULENAME_form_commerce_checkout_form_checkout_alter(&$form, &$form_state) {
  $form['#after_build'][] = 'MODULENAME_form_commerce_checkout_form_checkout_after_build';
}

/**
 * After build callback for commerce_checkout_form_checkout().
 */
function MODULENAME_form_commerce_checkout_form_checkout_after_build($form) {
  if (isset($form['account']['login'])) {
    $form['commerce_fieldgroup_pane__group_customer']['login'] = $form['account']['login'];
    $form['account']['#access'] = FALSE;
    unset($form['account']['login']);
  }
  return $form;
}