#' serie, and then calls the "jump prediction" function -- see "field" section -- to
#' adjust it based on the last observed values.
#'
+#' @usage f <- Forecaster$new(pjump) #warning: predictShape() is unimplemented
+#'
#' @field .params List of computed parameters (if applicable).
#' @field .pjump Function: how to predict the jump at day interface? The arguments of
#' this function are -- in this order: