def get_labels(rightside):
    met = {}
    met['brain'] = (
        1. * (rightside != 0).sum() / (rightside == 0).sum())
    met['tumor'] = (
        1. * (rightside > 2).sum() / ((rightside != 0).sum() + 1e-10))
    met['has_enough_brain'] = met['brain'] > 0.30
    met['has_tumor'] = met['tumor'] > 0.01
    return met

What I really meant is a way to search and select data based on metadata. For example has_tumor.

Also note how everything is still one single blob, to get one line of any of the files, one would need to download everything.