I need val losses in the output file log.json but i can't get them

[AntonioVispi]

Greetings,
in order to get the loss graphs during training, I would need both the train losses, which appear regular, and the val losses. I have trouble getting the latter to appear. I have seen in past issues, and I understood that to do this I have to change the setting from
workflow = [('train', 1)] to workflow = [('train', 1), ('val', 1)], but for some reason, this gives me an Error.
Have you got any idea to fix it?

This is the part where I changed the workflow cfg.

This is the error that arises

Thanks in advance.

[AntonioVispi]

I solved it!
I added these lines to the train command.
import copy val_dataset = copy.deepcopy(cfg.data.val)
val_dataset.pipeline = cfg.data.train.pipeline
datasets.append(build_dataset(val_dataset))

Thank you anyway.