Logical or Numeric. TRUE uses parallel::detectCores(). FALSE uses one, single core. You can also specify the number logical cores to use. Note that due to performance considerations, the number of cores defaults to one on Windows.
# NOT RUN {plot(packageRankTime(packages = "HistData", when = "last-week"))
plot(packageRankTime(packages = c("Rcpp", "rlang", "data.table"), when = "last-month"))
# }