code: def hashable(self):
          
  
          output = []
          values = self._get_values(self)
          for key in sorted(values.keys()):
              output.append('%s: %s' % (key, values[key]))
          # Unit separator is used here since the normalization process for
          # values moves any such character, and the keys are all dotted integers
          # or under_score_words
          return '\x1F'.join(output)
docs: :return:
              A unicode string that can be used as a dict key or in a set