--- exception([error_message])

    ꤷʤ self ֤ޤǤʤСȤΥԡ
    message ° error_message ˤ
    ֤ޤ

    raise ϡ¼Ūˡ㳰֥Ȥ exception 
    ᥽åɤθƤӽФǤ

