code: def _publish_grade(self, score, only_if_higher=None):
          
          grade_dict = {
              'value': score.raw_earned,
              'max_value': score.raw_possible,
              'only_if_higher': only_if_higher,
          }
          self.runtime.publish(self, 'grade', grade_dict)
docs: Publish a grade to the runtime.