def mark_points(data, marked_data_indexes):
    """
    Mark specific points.

    Parameters
    ----------
    data : tuple
        A value returned by the get_data() function.
    marked_data_indexes : ndarray
        An array containing indexes of points from data variable. The indexes
        come from marked points.

    Returns
    -------
    tuple
        A tuple with subtuples. Each subtuple contains points from data
        and is related to one index.
    """
    marked_data = ()
    if len(marked_data_indexes) == 0:
        return marked_data
    for single_data in data:
        dat = single_data[-1]
        marked_points = ()
        for index in marked_data_indexes:
            marked_points += dat[index],
        marked_data += marked_points,
    return marked_data
