def hexa_to_rgb(color):
    """Convert hexadecimal color to RGB."""
    r = int(color[1:3], 16)
    g = int(color[3:5], 16)
    b = int(color[5:7], 16)
    if len(color) == 7:
        return r, g, b
    elif len(color) == 9:
        return r, g, b, int(color[7:9], 16)
    else:
        raise ValueError('Invalid hexadecimal notation.')
