"None" is a valid job_status.

Jobs on a queue with no worker have a status of `None`. The if statement sees this as a falsy value, which results in job.status being evaluated, which then raises a deprecation error on recent versions of RQ.

There's no `defined` filter in django templates, but django casts all results to strings, so a status of `None` will have a length, whereas an undefined function will have a length of 0.