def draw_root_frets(draw, instrument, text_top_area, text_bottom_area,
    image_height, palette):
    """Add the frets to the root finder image"""
    for fret_num in list(range(1, instrument.number_of_frets)):
        fret_pos_x = fret_num * (instrument.fret_spacing / 4) + (instrument
            .top_gap / 2 + instrument.nut_width / 2)
        draw.line((fret_pos_x, text_top_area, fret_pos_x, image_height -
            text_bottom_area), palette.fret_colour, width=1)
    return draw
