Move mail & email confirm on Drupal registration

  $form['mail'] = $form['account']['mail'];
  $form['conf_mail'] = $form['account']['conf_mail'];
  $form['mail']['#weight'] = $form['field_first_name']['#weight'];
  $form['conf_mail']['#weight'] = $form['field_last_name']['#weight'];
  $form['field_first_name']['#weight'] -= 2;
  $form['field_last_name']['#weight'] -= 2;
  hide($form['account']['mail']);
  hide($form['account']['conf_mail']);
  array_splice($form['#groups']['group_about_you']->children, 2, 0, array('mail', 'conf_mail'));
  $form['#group_children']['mail'] ='group_about_you';
  $form['#group_children']['conf_mail'] ='group_about_you';