refactor CsstResult.files

        assert isinstance(status, CsstStatus)

        assert type(files) is list

        self.status = status

        self.file_list = files

        self.files = files

        self.output = output

    def __repr__(self):

        return f""" <CsstResult status={self.status}>

 - file_list: {self.file_list}

 - files: {self.files}

 - output: {self.output} \n

"""