public function getBirthday($format = 'Y-m-d')
    {
        $value = $this->getParameter('birthday');

        return $value ? $value->format($format) : null;
    }
public function getBirthday($format = 'Y-m-d')
    {
        $value = $this->getParameter('birthday');

        return $value ? $value->format($format) : null;
    }
public function getBirthday ( $ format = 'Y-m-d' ) { $ value = $ this -> getParameter ( 'birthday' ) ; return $ value ? $ value -> format ( $ format ) : null ; }
Get the cardholder's birthday.

@return string
Get the cardholder s birthday .