Use ConcatDataset with MultiImageMixDataset

[willcray]

Hello, I'm trying to use the CopyPaste data augmentation. I'm able to get it working by wrapping one of my many train datasets in the MultiImageMixDataset wrapper. I'd like to use it on all of my training datasets, which I aggregate using ConcatDataset. However, I get this error:

assert 'mix_results' in results
AssertionError

This is the same error that arises when you don't wrap a dataset in MultiImageMixDataset but attempt to use CopyPaste, MixUp, Mosaic, or another augmentation that's dependent on the 'mix_results' field, which MultiImageMixDataset injects.