code: def get_section2items(self, itemkey):
          
          sec_items = []
          section2usrnts = self.get_section2usrnts()
          for section, usrnts in section2usrnts.items():
              items = set([e for nt in usrnts for e in getattr(nt, itemkey, set())])
              sec_items.append((section, items))
          return cx.OrderedDict(sec_items)
docs: Collect all items into a single set per section.