Enable deletion of expired jobs

gistfile1.txt

// This will make sure expired jobs are deleted after XX days
add_filter( 'job_manager_delete_expired_jobs', '__return_true' );

// The default is 30 days, but you can change this with the following
add_filter( 'job_manager_delete_expired_jobs_days', 'change_job_manager_delete_expired_jobs_days' );

function change_job_manager_delete_expired_jobs_days() {
   return 30; // change this to the number of days you desired
}

This script doesn't work.. placed it in my functions..php and made a custom plugin for it. Both not working