docs: def append(self, item):
          """Append an item to the score set.
  
          item is a pair tuple, the first element of which is a valid dict
          key and the second of which is a numeric value.
          """
          if item in self:
              self.items[item[0]].append(item[1])
          else:
              self.items[item[0]] = [item[1]]