code: def _do_zero_width(self):
          
          self._do_retrieve(self.UCD_URL, self.UCD_IN)
          (version, date, values) = self._parse_category(
              fname=self.UCD_IN,
              categories=('Me', 'Mn',)
          )
          table = self._make_table(values)
          self._do_write(self.ZERO_OUT, 'ZERO_WIDTH', version, date, table)
docs: Fetch and update zero width tables.