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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def list_jobs(tail):
 """Show info about the existing crawler jobs."""

    query = (
        db.session.query(models.CrawlerJob)
        .order_by(models.CrawlerJob.id.desc())
    )
    if tail != 0:
        query = query.limit(tail)

    results = query.yield_per(10).all()
    _show_table(results=results)