def _expand_cloned(elements):
    return itertools.chain(*[x._cloned_set for x in elements])
Return whether index is a Series sliced from df
dataset/ETHPy150Open goFrendiAsgard/kokoropy/kokoropy/packages/sqlalchemy/sql/elements.py/_expand_cloned--crossover with--dataset/ETHPy150Open dask/dask/dask/dataframe/groupby.py/_GroupBy._is_grouped_by_sliced_column