modify ``val_loss_mean``
revised by this warning
***/lib/python3.*/site-packages/pytorch_lightning/utilities/distributed.py:25: RuntimeWarning: The metric you returned 1.234 must be a `torch.Tensor` instance, checkpoint not saved HINT: what is the value of val_loss in validation_epoch_end()?
This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
