code: def sorted_key_list(self):
          
          if not self.is_baked:
              self.bake()
          key_value_tuple = sorted(self.dct.items(),
                                   key=lambda x: x[1]['__abs_time__'])
          skl = [k[0] for k in key_value_tuple]
          return skl
docs: Returns list of keys sorted according to their absolute time.