code: def _record(self, entries):
          '''
          Return a string representing the Rock Ridge entry.
          Parameters:
           entries - The dr_entries or ce_entries to generate a record for.
          Returns:
           A string representing the Rock Ridge entry.
          '''
          outlist = []
          if entries.sp_record is not None:
              outlist.append(entries.sp_record.record())
          if entries.rr_record is not None:
              outlist.append(entries.rr_record.record())
          for nm_record in entries.nm_records:
              outlist.append(nm_record.record())
          if entries.px_record is not None:
              outlist.append(entries.px_record.record(self.rr_version))
          for sl_record in entries.sl_records:
              outlist.append(sl_record.record())
          if entries.tf_record is not None:
              outlist.append(entries.tf_record.record())
          if entries.cl_record is not None:
              outlist.append(entries.cl_record.record())
          if entries.pl_record is not None:
              outlist.append(entries.pl_record.record())
          if entries.re_record is not None:
              outlist.append(entries.re_record.record())
          for es_record in entries.es_records:
              outlist.append(es_record.record())
          if entries.er_record is not None:
              outlist.append(entries.er_record.record())
          if entries.ce_record is not None:
              outlist.append(entries.ce_record.record())
          for pd_record in entries.pd_records:
              outlist.append(pd_record.record())
          if entries.st_record is not None:
              outlist.append(entries.st_record.record())
          if entries.sf_record is not None:
              outlist.append(entries.sf_record.record())
          return b''.join(outlist)