code: def collect(self, top, sup, argv=None, parent=""):
          
          
          try:
              argv_copy = sd_copy(argv)
              return [self.repr(top, sup, argv_copy, parent=parent)], []
          except AttributeError as exc:
              print("#!!!!", exc)
              return [], []
docs: means this element is part of a larger object, hence a property of 
          that object