def rgb_to_hex(r, g, b):  # pylint: disable=invalid-name
    """
    Convert numeric r, g, b color channels to a hex standard #RRGGBBAA color format.

    Arguments:
    - r - red channel in (0, 255).
    - g - green channel in (0, 255).
    - b - blue channel in (0, 255).
    """
    return "#%02X%02X%02XFF" % (r, g, b)