hook.run.default is the default hookRun function. You can use it as
an advanced example of how to create your own hooRun function.hook.run.default(instance, candidate, extra.params, config)hookEvaluate is NULL, then this function returns the
output of evaluating the candidate, which must be a numerical value. Otherwise, it returns a string. By the default, this string is the
actual command-line call to the hook-run program. This information is
only used for debugging purposes if hookEvaluate fails later.