/**
  * @return string
  */
 function get_form_html()
 {
     $attributes = array('id' => $this->html_id(), 'name' => $this->html_name(), 'class' => $this->html_class() . (!empty($attributes['class']) ? " {$attributes['class']}" : ''));
     $form_html = WP_Metadata::get_element_html($this->html_tag(), $attributes, $this->get_form_fields_html());
     return "\n<!-- WP_Metadata Form -->\n\n{$form_html}";
 }