Write grouped and sorted GO IDs to GOs.

def wr_txt_nts(self, fout_txt, desc2nts, prtfmt=None):
        """Write grouped and sorted GO IDs to GOs."""
        with open(fout_txt, 'w') as prt:
            summary_dct = self._prt_txt_desc2nts(prt, desc2nts, prtfmt)
            if summary_dct:
                print(self.sortobj.grprobj.fmtsum.format(
                    ACTION="WROTE:", FILE=fout_txt, **summary_dct))
            else:
                print("  WROTE: {TXT}".format(TXT=fout_txt))