code: def prt_hier_all(self, prt=sys.stdout):
          
          # Print: [biological_process, molecular_function, and cellular_component]
          items_list = set()
          for goid in ['GO:0008150', 'GO:0003674', 'GO:0005575']:
              items_list.update(self.prt_hier_down(goid, prt))
          return items_list
docs: Write hierarchy for all GO Terms in obo file.