function disconnect ( a: KaryGraph.API.AbstractionLayer.DotObjectOrDotID, 
                          b: KaryGraph.API.AbstractionLayer.DotObjectOrDotID ): boolean {
        let d1 = KaryGraph.API.AbstractionLayer.GetDotByDotOrId( a );
        let d2 = KaryGraph.API.AbstractionLayer.GetDotByDotOrId( b );
        return d1.DisconnectFrom( d2 );