code: private function attachLabels($widgets_by_id, $labels)
      {
          foreach ($labels as $label) {
              $for = $label->getFor();
              if ($for and isset($widgets_by_id[$for])) {
                  $text = $label->getText();
                  foreach ($widgets_by_id[$for] as $widget) {
                      $widget->setLabel($text);
                  }
              }
          }
      }
docs: Called at the end of a parse run.
  Attaches any non-wrapping labels to their form elements.
  
  @param array $widgets_by_id     Cached SimpleTag hash.
  @param array $labels            SimpleTag label elements.