code: def _init_go_sets(self, go_fins):
          
          go_sets = []
          assert go_fins, "EXPECTED FILES CONTAINING GO IDs"
          assert len(go_fins) >= 2, "EXPECTED 2+ GO LISTS. FOUND: {L}".format(
              L=' '.join(go_fins))
          obj = GetGOs(self.godag)
          for fin in go_fins:
              assert os.path.exists(fin), "GO FILE({F}) DOES NOT EXIST".format(F=fin)
              go_sets.append(obj.get_usrgos(fin, sys.stdout))
          return go_sets
docs: Get lists of GO IDs.