Function to turn a MS/PC-DOS colour code into a Rich colour style markup string

rich_dos_colour.py

def rich_dos_colour( color: int ) -> str:
    """Convert a MS/PC-DOS colour attribute to Rich style text.

    :param int colour: The MS/PC-DOS colour attribute.
    :returns: A Rich BBCode-style markup string for the colour.
    :rtype: str
    """
    assert 0 <= color <= 0xFF, "DOS colour codes must be 0 to 255 inclusive"
    return "[color({}) on color({})]".format(
        *reversed( divmod( color, 0x10 ) )
    )

Turns out, this doesn't quite work because the colour numbers used by Rich don't map to those used by 8bit DOS.