code: def on_epoch_end(self, last_metrics, **kwargs):
          "Set the final result in `last_metrics`."
          return add_metrics(last_metrics, self.val/self.countf on_epoch_end(self, last_metrics, **kwargs):
          "Set the final result in `last_metrics`."
          return add_metrics(last_metrics, self.val/self.count)
docs: Set the final result in `last_metrics`.