Function _is_index_level_reference

dask/dataframe/multi.py:254–260

(x, key)

    """

    def _is_index_level_reference(x, key):
        return (
            x.index.name is not None
            and (np.isscalar(key) or isinstance(key, tuple))
            and key == x.index.name
            and key not in getattr(x, "columns", ())
        )

    if isinstance(columns_or_index, list):
        return any(_is_index_level_reference(df, n) for n in columns_or_index)