Fix Union Model
Fix Union Model

that was completely broken :/

now all tests pass

kaufmo/koala-framework,nsams/koala-framework,yacon/koala-framework,yacon/koala-framework,nsams/koala-framework,koala-framework/koala-framework,kaufmo/koala-framework,yacon/koala-framework,koala-framework/koala-framework,kaufmo/koala-framework,nsams/koala-framework