Django Sequence Returns an empty list

Hey guy I'm new to Django. I am using Rest API with Django to interact with my Android app. I have the data I need in the quest variable . Since there are several questions, I am using a filter instead of get.

This is my Views.py:

class MapertablesViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows groups to be viewed or edited.
    """
    queryset = Mapertables.objects.all()
    serializer_class = MapertablesSerializer
    lookup_field = 'category_id'

    def get_queryset(self):
        #print self.kwargs['category_id']
        maps = Mapertables.objects.filter(category_id=self.kwargs['category_id'])
        #queryset = list(maps)
        #queryset =  serializers.serialize('json',maps)
        #print "AAAA ",queryset
        i = 0
        #quest ={}
        queryset = []
        queslist = []
        for question in maps:
            quest = {}
            quest['question'] = question.question_id
            #print 'qqqq  ',question.question_id
            #queryset =  serializers.serialize('json',[question,])
            choices = Choice.objects.filter(question=question.question_id)
            print choices
            #aaa = chain(question,choices)
            #print aaa
            #queryset =  serializers.serialize('json',[question,choices,])
            j = 0
            for option in choices:
                quest[j] = option.choice_text
                j += 1
            print 'data Here ',quest
            #data Here  {0: u'Highbury', 1: u'Selhurst Park', 2: u'The Dell', 3: u'Old Trafford', 'question': <Question: At which ground did Eric Cantona commit his "Kung Fu" kick ?>}
            serializer_class = CoustomeSerializer(queryset, many=True)
            print serializer_class.data
            #[]
            json = JSONRenderer().render(serializer_class.data)
            print 'JSON',json
            #[]
            i += 1

        queryset = queslist
        serializer_class = CoustomeSerializer(queryset,many=True)
        return queryset
        #print "questions",queslist
        #print "Ser ",ser.data

      

        
        
        
      

    

This is my serializers.py:

class  MapertablesSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model =  Mapertables
        fields = ('question_id','category_id')


class CoustomeSerializer(serializers.HyperlinkedModelSerializer):
    #questions =  MapertablesSerializer(source='question_id')
    #choices = ChoiceSerializer(source='choice_text')
    class Meta:
        model = Question,Choice,Category
        fields = ('choice_text','choice_text','choice_text','choice_text','question_id')

      

        
        
        
      

    

URL that is defined for display:    http://127.0.0.1:8000/mapers/   Exception type: KeyError Exception value: 'category_id'

when I ask for a specific category, it returns:    http://127.0.0.1:8000/mapers/2/   {"detail": "Not Found". }

The Model.py file looks like this:

from django.db import models

# Create your models here.
class Category(models.Model):
    category_name = models.CharField(max_length=200,default='1')
    def __str__(self):
        return self.category_name


class Question(models.Model):
    question_text = models.CharField(max_length=200)
    #category_name = models.ForeignKey(Category)
    pub_date = models.DateTimeField('date published')
    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)
    was_published_recently.admin_order_field = 'pub_date'
    was_published_recently.boolean = True
    was_published_recently.short_description = 'Published recently?'
    def __str__(self):
        return self.question_text


class Mapertables(models.Model):
    category_id = models.ForeignKey(Category)
    question_id = models.ForeignKey(Question)


class Choice(models.Model):
    question = models.ForeignKey(Question)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)
    def __str__(self):
        return self.choice_text

      

        
        
        
      

    

I want to get all category related questions and there is a selection from the select module, why are all things in get_queryset.

Please tell me how to get all the data I need in the MapertablesViewSet class

Thanks in advance, if you want me to submit the complete project, just let me know and I will zip and upload to disk or something.