    def extract_zip(self):
        assert self.FILE_COUNT>0
        try:
            with zipfile.ZipFile(self.archive_path, "r") as zip:
                content = zip.read("ROMS/6809/EXT_BASIC_NO_USING.hex")
                out_filename=os.path.join(self.ROM_PATH, "EXT_BASIC_NO_USING.hex")
                with open(out_filename, "wb") as f:
                    f.write(content)

                print("%r extracted" % out_filename)
                self.post_processing(out_filename)

        except BadZipFile as err:
            msg = "Error extracting archive %r: %s" % (self.archive_path, err)
            log.error(msg)
            raise BadZipFile(msg)