code: def sort(self):
          self._matches.sort_values(
              by=[constants.SIZE_FIELDNAME, constants.NGRAM_FIELDNAME,
                  constants.COUNT_FIELDNAME, constants.LABEL_FIELDNAME,
                  constants.WORK_FIELDNAME, constants.SIGLUM_FIELDNAME],
              ascending=[False, True, False, True, True, True], inplace=True)