/**
  * Кэш терминов
  *
  * @return CArrayList|null
  */
 private static function getCacheLegacyTerms()
 {
     if (is_null(self::$_cacheLegacyTerms)) {
         self::$_cacheLegacyTerms = new CArrayList();
     }
     return self::$_cacheLegacyTerms;
 }