Pagination error

serializers.py

# django
from django.forms import widgets

# 3rd party apps
from rest_framework import serializers, pagination


from base.models import Document, Sentence
    
class DocumentSerializer(serializers.Serializer):

    _id = serializers.CharField(required=True, max_length=None)
    text = serializers.CharField(required=True, max_length=None)

    def restore_object(self, attrs, instance=None):

        print 'attrs:', attrs
        print 'instance:', instance

        # update existing instance
        if instance:
            instance._id = attrs.get('_id', instance._id)
            instance.text = attrs.get('text', instance.text)
            return instance

        # Create new instance
        return Document(**attrs)

views.py

# django
from django.shortcuts import get_object_or_404, render, render_to_response
from django.contrib.auth.models import User
from django.views.generic.base import RedirectView, View
from django.conf import settings
from django.template import RequestContext

# 3rd party apps
from rest_framework import status
from rest_framework import viewsets
from rest_framework.parsers import JSONParser
from rest_framework.response import Response
from rest_framework.decorators import link
from rest_framework import renderers

# local
from base.models import Tag, Decision
from base.serializers import SentenceSerializer, DocumentSerializer
from mongo_connection import mongo_connection

class MoneyballViewSet(viewsets.GenericViewSet):
    """This is an abstract base class for the ViewSets defined in this
    module.

    """
    # this is used as the base name by the router in urls.py, and also
    # can be used for nicely formatting error messages. It should be
    # overwritten in base classes.
    base_name = 'moneyball'
    paginate_by = 20
    


class DocumentViewSet(MoneyballViewSet):
    """This is the view set for dealing with documents. It's what the API
    does with requests for documents.

    """
    # used by router. see base class comment
    base_name = 'document'

    # testing a GET request task with the TaskRouter
    # @link(renderer_classes=[renderers.StaticHTMLRenderer])
    # def textsearch(self, request, *args, **kwargs):
    #     print 'textsearch'
    #     return Response("heyyyyy!", status=status.HTTP_200_OK)

    def list(self, request, format=None):

        for k,v in request.DATA.iteritems():
            print k, ':', v

        collection = mongo_connection()

        # get the query from the request
        batch_size = request.DATA.get('batch_size', 20)
        query = request.DATA.get("query",{})
        queryset = collection.find(query).batch_size(batch_size)

        # serialize and respond
        serializer = DocumentSerializer(queryset, many=True)
        return Response(serializer.data, status=status.HTTP_200_OK)