examples/legacy/pytorch-lightning/run_glue.py/GLUETransformer/validation_epoch_end
class GLUETransformer:    def validation_epoch_end(self, outputs: list) -> dict:
        ret, preds, targets = self._eval_end(outputs)
        logs = ret["log"]
        return {"val_loss": logs["val_loss"], "log": logs, "progress_bar": logs}