Create binary class dataset from multiple class dataset

Yes. And how should I do that? I just found this Change labels in Data Loader today. I will try this later. What does train parameter do besides giving the train_labels attributes?

Also, I want to only use part of other labels so I have a balanced training dataset. For example, the original dataset has 3000 images for each class. I want to preserve 3000 images for forest class. And I want a mix of other 5 classes as a total of 3000 images. Any ideas?