Ambient light

[Enlil]

<node3d>.ambient mentions "the ambient property determines what colors from the ambient light the node will reflect. The final ambient color of the node is the ambient material color multiplied by the ambient color of the light. If the ambient color is [1,0,0] and the ambient light is [1,1,1], then the node will appear red."

But there doesn't appear to be any documentation on changing the ambient light, just the ambient property of objects. Is there a way to change the ambient light?

Thanks,
Christian