columnar::EgammaDef Node1 columnar::EgammaDef + idName   Node3 columnar::MutableContainer Id< EgammaDef > + isMutable   Node1->Node3 Node2 columnar::RegularContainer Id< xAOD::Egamma, xAOD ::EgammaContainer > + isContainerId + regularObjectId + variantObjectId + regularColumnAccessorArray + isMutable + perEventRange + perEventId   Node2->Node1