Using subset of dataset

[ellesecotterill]

Hi,

I'd like to train a model using multiple datasets, however I'd like to only use a fraction of one of the datasets and shuffle which data is used each epoch. Is this available functionality in Detectron2? For example, if I have two datasets train_set_0 and train_set_1, I'd like to train using all of train_set_0 and 50% of 'train_set_1, and for each epoch use a different random 50% subset of train_set_1.