def is_color_light(rgb_hex_color_string):
    """ return true if the given html hex color string is a "light" color
    https://en.wikipedia.org/wiki/Relative_luminance
    """
    r, g, b = rgb_hex_color_string[:2], rgb_hex_color_string[2:4], \
              rgb_hex_color_string[4:]
    r, g, b = [int(n, 16) for n in (r, g, b)]
    y = (0.2126 * r) + (0.7152 * g) + (0.0722 * b)

    return y > 128