docs: @Override
      public OptionalThing<Cron4jJob> findJobByKey(LaJobKey jobKey) {
          assertArgumentNotNull("jobKey", jobKey);
          final Cron4jJob found = jobKeyJobMap.get(jobKey);
          return OptionalThing.ofNullable(found, () -> {
              String msg = "Not found the job by the key: " + jobKey + " existing=" + jobKeyJobMap.keySet();
              throw new JobNotFoundException(msg);
          });
      }