public function setSecond($second)
    {
        if (Format::isIdentifier($second)) {
            $this->second = $second;
        } else {
            $msg = "'${second}' is an invalid QTI identifier.";
            throw new InvalidArgumentException($msg);
        }
    }
public function setSecond($second)
    {
        if (Format::isIdentifier($second)) {
            $this->second = $second;
        } else {
            $msg = "'${second}' is an invalid QTI identifier.";
            throw new InvalidArgumentException($msg);
        }
    }
public function setSecond ( $ second ) { if ( Format :: isIdentifier ( $ second ) ) { $ this -> second = $ second ; } else { $ msg = "'${second}' is an invalid QTI identifier." ; throw new InvalidArgumentException ( $ msg ) ; } }
Set the second identifier of the pair.

@param string $second A QTI Identifier.
@throws \InvalidArgumentException If $identifier is not a valid QTI Identifier.
Set the second identifier of the pair .