public function getValue()
  {
    $value = parent :: getValue();

    if(!$default_value = $this->getDefaultValue())
      $default_value = reset($this->choice_list);

    if (!array_key_exists($value, $this->choice_list))
      return $default_value;
    else
      return $value;
  }
 public function getValue()
 {
   return ContainerFormElement :: getValue();
 }