insp = inspection.alias('insp')
latest_restaurant_inspections = select(
    [restaurant, inspection.c.id, inspection.c.date, violation.c.code], 
    and_(
        inspection.c.date==(select([func.max(insp.c.date)], insp.c.restaurant_id==restaurant.c.id)),
        violation.c.code=='c1'
        ),
        from_obj=[restaurant.join(inspection).join(inspection_violation).join(violation)],
    )