def _invert(color, **kwargs):
    """ Returns the inverse (negative) of a color.
        The red, green, and blue values are inverted, while the opacity is left alone.
    """
    col = ColorValue(color)
    args = [
        255.0 - col.value[0],
        255.0 - col.value[1],
        255.0 - col.value[2],
        col.value[3],
    ]
    inverted = ColorValue(args)
    return inverted