modellist_fit <- caretEnsemble::caretList(
returnShipment ~.,
data = trainSet,
trControl = caret::trainControl(
  method = "boot",
  number = 2,
  savePredictions = TRUE,
  classProbs = TRUE,
  index = caret::createResample(trainSet$returnShipment, 2),
  verboseIter = TRUE
),
tuneList = list(
  xgb = caretEnsemble::caretModelSpec(method = "xgbTree", tuneGrid = expand.grid(nrounds = 50, max_depth = 2, eta = 0.3, gamma = 0, colsample_bytree = 0.6, min_child_weight = 1, subsample = 1)),
  nnet = caretEnsemble::caretModelSpec(method = "nnet", tuneGrid = expand.grid(size = 15, decay = 0.1))
)
)