def _get_split(super_categories, train_set):
    """Get number of classes per experience, and
    the total order of the classes."""
    per_exp_classes, fixed_class_order = {}, []
    for idx, supcat in enumerate(super_categories):
        new_cats = list(train_set.cats_per_supcat[supcat])
        fixed_class_order += new_cats
        per_exp_classes[idx] = len(new_cats)
    return per_exp_classes, fixed_class_order
Get number of classes per experience, and
    the total order of the classes.
avalanche/benchmarks/classic/cinaturalist.py