vector gradients

How can I apply gradient colors on vector shapes?
I was trying to write a node using the Colors lib (http://nodebox.net/code/index.php/Colors)
but this led to exeption in the lib

java.lang.RuntimeException: java.util.concurrent.ExecutionException: nodebox.util.LoadException: Error while loading init.py: Traceback (most recent call last):
File "F:\art\colors_init_.py", line 582, in <module>
class Color(BaseColor):
java.lang.InstantiationException: can't subclass final class

The Colors library was written for NodeBox 1, not for 3. But we're working on a port, it should be ready somewhere in the weeks to come.