Print grouped and sorted GO IDs.

def wr_xlsx_nts(self, fout_xlsx, desc2nts, **kws_usr):
        """Print grouped and sorted GO IDs."""
        # KWS_XLSX: top_n section_prt section_sortby
        # Adjust xlsx keyword args
        kws_xlsx = self._get_xlsx_kws(**kws_usr)
        # KWS_SHADE: shade_hdrgos hdrgo_prt section_sortby top_n
        shade_hdrgos = self._get_shade_hdrgos(**kws_usr)
        self._adjust_prt_flds(kws_xlsx, desc2nts, shade_hdrgos)
        # 1-D: data to print is a flat list of namedtuples
        if 'flat' in desc2nts:
            nts = desc2nts.get('flat')
            # sys.stdout.write("FLAT NTS: {FLDS}\n".format(FLDS=" ".join(next(iter(nts))._fields)))
            wr_xlsx(fout_xlsx, nts, **kws_xlsx)
        # 2-D: data to print is a list of [(section, nts), ...
        else:
            sections_hdrgos = desc2nts.get('sections')
            wr_xlsx_sections(fout_xlsx, sections_hdrgos, **kws_xlsx)