GAE Python Data Loader that handles Next & Previous correctly

DataLoaderNextPrevious.py

class LoadHelper:
    PAGE_SIZE = 10
    """ load objects, ordered by a parameter
        supports next & previous"""
    def loadByString(self, request, order, filter):
        next = request.get('next')
        prev = request.get('prev')

        query = MyObject.all()

        if prev:
            query.order("-"+order)
        else:
            query.order(order)

        if filter:
            query.filter(filter,True)

        if next:
            query.filter(order + " >= " , next)
        elif prev:
            query.filter(order + " <= " , prev)

        list = query.fetch(LoadHelper.PAGE_SIZE )
        if prev:
            list.reverse()

        return list


class ObjectHandler(webapp.RequestHandler):
    url = '/web/something'
    def get(self):
        list = LoadHelper().loadByString(self.request, 'name', 'online')

        next=''
        prev=''
        if list[0]:
            prev = list[0].name
            next = list[-1].name
        
        path = os.path.join(os.path.dirname(__file__), 'template.html')
        self.response.out.write(template.render(path, dict() ))