Returns a list of jobs that are stored in the database.

def get_jobs(self, job_ids = None):
    """Returns a list of jobs that are stored in the database."""
    if job_ids is not None and len(job_ids) == 0:
      return []
    q = self.session.query(Job)
    if job_ids is not None:
      q = q.filter(Job.unique.in_(job_ids))
    return sorted(list(q), key=lambda job: job.unique)