/**
  * Output post meta settings.
  *
  * @since 1.0.0
  *
  * @return string HTML for entire post meta settings.
  */
 public function do_post_meta_settings()
 {
     echo '<div class="rae-post-meta-checkboxes">';
     if ($this->plugin->post_meta_exists_to_enable()) {
         printf('<p>%s</p>', __('Select which post meta to include in REST API response.', 'rest-api-enabler'));
         $this->do_post_meta_check_buttons();
         $this->do_post_meta_checkboxes();
     } else {
         printf('<p>%s</p>', __('There is no unprotected post meta to enable.', 'rest-api-enabler'));
     }
     echo '</div>';
 }