code: def normalize(self):
          
          if self.should_collapse(): return self.collapse()
          elif self.number_of_values == 1: return list(self._si_set)[0]
          else:
              for si in self._si_set:
                  self._update_bits(si)
              return self
docs: Return the collapsed object if ``should_collapse()`` is True, otherwise return self.
  
          :return: A DiscreteStridedIntervalSet object.