def add_frame_div_parent(cell_info):
    """
    Adds the frame a cells parent divides on to cell info.

    Args:
        cell_info (dict): dict that maps cells to cell info
    Returns:
        dict: cell info with added frame_div_parent
    """
    new_info = cell_info.copy()
    for info in new_info.values():
        if info['parent']:
            parent = info['parent']
            info['frame_div_parent'] = new_info[parent]['frame_div']
        else:
            info['frame_div_parent'] = None
    return new_info