code: def compute(cls, observation, prediction, key=None):
          
          assert isinstance(observation, (dict, float, int, pq.Quantity))
          assert isinstance(prediction, (dict, float, int, pq.Quantity))
  
          obs, pred = cls.extract_means_or_values(observation, prediction,
                                                  key=key)
          value = pred / obs
          value = utils.assert_dimensionless(value)
          return RatioScore(value)
docs: Compute a ratio from an observation and a prediction.