code: def compression_details(self):
          
          event_type = self.findtext("event_type")
          if event_type != "compression":
              raise AttributeError(
                  'PREMIS events of type "{}" have no compression'
                  " details".format(event_type)
              )
          parsed_compression_event_detail = self.parsed_event_detail
          compression_program = _get_event_detail_attr(
              "program", parsed_compression_event_detail
          )
          compression_algorithm = _get_event_detail_attr(
              "algorithm", parsed_compression_event_detail
          )
          compression_program_version = _get_event_detail_attr(
              "version", parsed_compression_event_detail
          )
          archive_tool = {"7z": "7-Zip"}.get(compression_program, compression_program)
          return compression_algorithm, compression_program_version, archive_tool
docs: Return as a 3-tuple, this PREMIS compression event's program,
          version, and algorithm used to perform the compression.