implement start_br for exhaustive strategy

    # if no seed given, compute it from other parameters, so that same params => same seed

    if seed is None:

        seed = brs.sum() + STRATEGIES.index(strategy) + switch_time + length_frames

        if starting_br is not None:

            seed += starting_br

    random.seed(seed)

    if strategy == "exhaustive":

            random.shuffle(split_permuts[i])

        split_permuts = np.asarray(split_permuts)

        brs = np.concatenate([split_permuts[:, i] for i in range(n)])

        if starting_br is not None:

            # brs is still a 2-D array here

            # find first row with starting br in first column, then roll array by that amount

            i_row, i_col = np.where(brs == starting_br)

            idx_col = np.where(i_col == 0)[0][0]

            shift = i_row[idx_col]

            brs = np.roll(brs, -shift, axis=0)

    elif strategy == "random":

        brs = list()