def METHOD_NAME(cls):
    cache_key = 'mapdata:max_bounds:%s:%s' % (cls.__name__, MapUpdate.current_cache_key())
    result = cache.get(cache_key, None)
    if result is not None:
        return result
    result = cls.objects.all().aggregate(models.Min('left'), models.Min('bottom'),
                                         models.Max('right'), models.Max('top'))
    result = ((float(result['left__min'] or 0), float(result['bottom__min'] or 0)),
              (float(result['right__max'] or 10), float(result['top__max'] or 10)))
    cache.set(cache_key, result, 900)
    return result