com.thoughtworks.deeplearning.DifferentiableCoproduct
(cConsLayerOps: CConsLayerOps[Input, HeadData, HeadDelta, TailData, TailDelta]).choice(caseHead)(caseTail)(headToLayer, tailToLayer, lub, commonToLayer)
(cConsLayerOps: CConsLayerOps[Input, HeadData, HeadDelta, TailData, TailDelta]).head
(cConsLayerOps: CConsLayerOps[Input, HeadData, HeadDelta, TailData, TailDelta]).isInl
(cConsLayerOps: CConsLayerOps[Input, HeadData, HeadDelta, TailData, TailDelta]).tail