throw new IllegalArgumentException("Only 'color' scheme is recognized " + colorURI);
if (!"rgb".equals(colorURI.authority()))
throw new IllegalArgumentException("Only 'rgb' authority is recognized " + colorURI);
if (colorURI.segmentCount() != 3)
throw new IllegalArgumentException("Color must have 3 segments (r, g, b) " + colorURI);
return colorURI;
}