/**
  * Abstract method to find matches in lookup tables.
  *
  * @param string $table
  * @param string $code
  * @return mixed description of response code if valid, otherwise false
  * @access protected
  */
 protected function _lookup($table, $code)
 {
     $_this =& CyberSourceAppendices::getInstance();
     if (isset($_this->{$table}[$code])) {
         $code = $_this->{$table}[$code];
     } else {
         $code = false;
     }
     return $code;
 }