def new2old ( self ) :
    "str"
    :
        self . sequences . states . new2old ( )
    except AttributeError
        pass

def new2old ( self ) :
    "str"
    try :
        self . sequences . states . new2old ( )
    except AttributeError :
        pass

次に示すpythonコードの誤りを修正しなさい。