code: def grouping_val(self):
          
          grouping = self.grouping
          if grouping is None:
              return ST_Grouping.STANDARD
          val = grouping.val
          if val is None:
              return ST_Grouping.STANDARD
          return val
docs: Return the value of the ``./c:grouping{val=?}`` attribute, taking
          defaults into account when items are not present.