Can't select "Lambda ARN" in endpoint for Skills Set "Color Expert" example

I'm trying to follow the instructions for creating the example Color Expert skill. Everything goes OK until I try to add an endpoint and the only choice it gives me for endpoint type is "API Gateway" while the instuctions say select "Lambda ARN (Amazon Resource Name)" and enter the ARN (which I have). I've tried both the Python and NodeJS versions and have the same problem.