question: Multiple Validation Sets
context: Hello, I'm trying to validate my model on multiple subsets of the initial validation set to compare performance. Reading this page I got the idea that returning a list contaning the multiple Dataloaders would be enough. My val_dataloader method became the following:
  
  But this isn't working properly. I get the following error: "TypeError: validation_step() takes 3 positional arguments but 4 were given"
  (it worked properly when I only used 1 validation Dataloader).
  What am I doing wrong? Can someone help me with this? Or just point me to some more documentation on this.
  Thanks in advance!
answer: you must be missing the additional dataloader_idx required in the validation_step for multiple dataloaders
  docs: https://pytorch-lightning.readthedocs.io/en/latest/guides/data.html#multiple-validation-test-predict-dataloaders