public function get_index($raw = false)
 {
     if ($raw === false) {
         $raw = $this->get_raw();
     }
     $id = $this->Tag->id();
     $out = array();
     if (is_array($raw)) {
         $Collections = new PerchContent_Collections();
         $out = $Collections->get_indexed_from_ids($this->Tag->collection(), $raw, $id);
     }
     return $out;
 }