code: def _chk_hdrgoids(hdrgos):
          
          goid = next(iter(hdrgos))
          if isinstance(goid, str) and goid[:3] == "GO:":
              return
          assert False, "HDRGOS DO NOT CONTAIN GO IDs: {E}".format(E=goid)
docs: Check that hdrgo set is a set of GO IDs.