Get sorted items for any model in any order

# -*- coding: UTF-8 -*-
from django.template import Library, Node ,TemplateSyntaxError
from django.db.models import get_model
import re
from datetime import datetime

register = Library()

class GetItemsNode(Node):
    def __init__(self, model, num, by, varname):
        self.num, self.varname = num, varname
        self.model = get_model(*model.split('.'))
        self.by = by

    def render(self, context):
        if hasattr(self.model, 'publicmgr') and not context['user'].is_authenticated():
            context[self.varname] = self.model.publicmgr.all().order_by(self.by)[:self.num]
            context[self.model.__name__.lower()+'_count']= self.model.publicmgr.count()
        
        else:
            context[self.varname] = self.model.objects.all().order_by(self.by)[:self.num]
            context[self.model.__name__.lower()+'_count'] = self.model.objects.count()   

        return  ''
        
        
def get_sorted_items(parser, token):
    bits = token.contents.split()
    if len(bits) != 7:
        raise TemplateSyntaxError, "get_sorted_items tag takes exactly 6 arguments"
    if bits[3] != 'by':
        raise TemplateSyntaxError, "third argument to get_sorted_items tag must be 'by'"
    if bits[5] != 'as':
        raise TemplateSyntaxError, "fivth argument to get_sorted_items tag must be 'as'"
    return GetItemsNode(bits[1], bits[2],bits[4], bits[6])
    
get_sorted_items = register.tag(get_sorted_items)


       <ul id="right_column">
        
        <li id="news_portlet" class="portlet">
        <h2>News</h2>
            <div class="portlet_body">
            {% get_sorted_items cms.news 5 by -created_on as items %}
            {% include 'snippets/dl.html' %}
            {% if news_count > items|length %}more...{% endif %}
            </div>
        </li>
        <li id="event_portlet" class="portlet">
        <h2>events</h2>
            <div class="portlet_body">
            {% get_sorted_items cms.event 5 by date as items %}
            {% include 'snippets/dl.html' %}
            {% if event_count > items|length %}more...{% endif %}
            </div>
        </li>
    </ul>