forget                  Forget past results. Resets the cache of a
                        memoised function.
has_cache               Test whether a memoised function has been
                        cached for particular arguments.
is.memoised             Test whether a function is a memoised copy.
                        Memoised copies of functions carry an attribute
                        'memoised = TRUE', which is.memoised() tests
                        for.
memoise                 Memoise a function.
timeout                 Return a new number after a given number of
                        seconds
