local({
  previous_options <- options(warn = 2, digits = 8, stringsAsFactors = FALSE)
  on.exit(options(previous_options), add = TRUE)
  capacity <- 12L
  requested <- 8L
  if (requested <= 0L) {
    result <- "invalid quantity"
  } else if (requested > capacity) {
    result <- "over capacity"
  } else {
    result <- "within capacity"
  }
  cat(result, "\n")
  invisible(NULL)
})