arrayOrNull <- setClassUnion("array or NULL",c("array","NULL"))

BowtieData <- setClass("BowtieData",
                       representation(obs= "array", act = "array",
                                      suc = "array or NULL"))

BowtieSimulationData <- setClass("BowetieSimulationData",
                                 representation(truth="array",est="array",
                                                params="list",
                                                paramsFollowTime = "logical"),
                                 contains="BowtieData")