'Modifies the properties of a single job. Modifications are passed to this method as extra keyword arguments.
:param str|unicode job_id: the identifier of the job
:param str|unicode jobstore: alias of the job store that contains the job'

def modify_job(self, job_id, jobstore=None, **changes):

    with self._jobstores_lock:
        (job, jobstore) = self._lookup_job(job_id, jobstore)
        job._modify(**changes)
        if jobstore:
            self._lookup_jobstore(jobstore).update_job(job)
    self._dispatch_event(JobEvent(EVENT_JOB_MODIFIED, job_id, jobstore))
    self.wakeup()
