f a multi-index to multi-index join.
    Depending on the type of join, this method restores the appropriate
    dropped levels of the joined multi-index.
    The method relies on lindexer, rindexer which hold the index positions of
    left and right, where a join was feasible

    Parameters
    ----------
    left : MultiIndex
        left index
    right : MultiIndex
        right index
    dropped_level_names : str array
        list of non-common level names
    join_index : Index
        the index of the join between the
        common levels of left and right
    lindexer : np.ndarray[np.intp]
        left indexer
    rindexer : np.ndarray[np.intp]
        right indexer

    Returns
    -------
    levels : list of Index
        levels of combined multiindexes
    labels : np.ndarray[np.intp]
        labels of combined multiindexes
    names : List[Hashable]
        names of combined multiindex levels

    rŠ