code: def wr_txt_section_hdrgos(self, fout_txt, sortby=None, prt_section=True):
          
          sec2d_go = self.grprobj.get_sections_2d()    # lists of GO IDs
          sec2d_nt = self.get_sections_2dnt(sec2d_go)  # lists of GO Grouper namedtuples
          if sortby is None:
              sortby = self.fncsortnt
          with open(fout_txt, 'w') as prt:
              self.prt_ver(prt)
              prt.write("# GROUP NAME: {NAME}\n".format(NAME=self.grprobj.grpname))
              for section_name, nthdrgos_actual in sec2d_nt:
                  if prt_section:
                      prt.write("# SECTION: {SECTION}\n".format(SECTION=section_name))
                  self.prt_ntgos(prt, nthdrgos_actual)
                  if prt_section:
                      prt.write("\n")
              dat = SummarySec2dHdrGos().summarize_sec2hdrgos(sec2d_go)
              sys.stdout.write(self.grprobj.fmtsum.format(
                  GO_DESC='hdr', SECs=len(dat['S']), GOs=len(dat['G']),
                  UNGRP=len(dat['U']), undesc="unused",
                  ACTION="WROTE:", FILE=fout_txt))
          return sec2d_nt
docs: Write high GO IDs that are actually used to group current set of GO IDs.