def create_pool(name, slots, description, session=None):
    """Create a pool with a given parameters."""
    if not (name and name.strip()):
        raise AirflowBadRequest("Pool name shouldn't be empty")

    try:
        slots = int(slots)
    except ValueError:
        raise AirflowBadRequest("Bad value for `slots`: %s" % slots)

    session.expire_on_commit = False
    pool = session.query(Pool).filter_by(pool=name).first()
    if pool is None:
        pool = Pool(pool=name, slots=slots, description=description)
        session.add(pool)
    else:
        pool.slots = slots
        pool.description = description

    session.commit()

    return pool
Create a pool with a given parameters.