Get the best model score without checkpoint files

[pandegaabyan]

The ModelCheckpoint and trainer.checkpoint_callback.best_model_score allow us to get the best model score. However, if arguments save_last=False and save_top_k=0 are set (since I don't want to store any checkpoint file), trainer.checkpoint_callback.best_model_score returns None. How to get the best model score without storing checkpoint files? The scores are logged using the Lightning Module method log().

I know that I can easily store it in the Lightning Module attribute or other manual approach. I just wonder if lightning has that feature out of the box.