local({
  previous_options <- options(warn = 2, digits = 8, stringsAsFactors = FALSE)
  on.exit(options(previous_options), add = TRUE)
  # Each value describes one fictional session.
  visits <- c(8, 12, 10)
  label <- "Room #2"
  cat(label, "has", length(visits), "sessions\n")
  invisible(NULL)
})