I am getting a problem in django serialization

Here is my model for the state 

class State(models.Model):
    class Translation(translation.Translation):
        name = models.CharField(max_length=64)

    capital     = models.ForeignKey('City', related_name="state_capital", null=True)
    country     = models.ForeignKey(Country, related_name="state_country", null=True)
    latitude    = models.DecimalField(max_digits=9, decimal_places=6, default=Decimal("0.0"))
    longitude   = models.DecimalField(max_digits=9, decimal_places=6, default=Decimal("0.0"))
    code        = models.CharField(max_length=2)

Based on county_id i am filtering the states name and tried to convert in json format so that i can update the select box .

But I am getting while doing this .

<django.utils.functional.__proxy__ object at 0x7feaac2761d0> is not JSON serializable

Here is my views .

def get_getstate(request):
    catid = request.GET['catid']
    get_related_subcategory = State.objects.filter(country_id = catid)

    json_models = serializers.serialize("json", get_related_subcategory)
    return HttpResponse(json_models, mimetype="application/javascript")

Please help me outto solve this error .

Update

I also tried like this 

from django.core.serializers.json import Serializer as JSONSerializer
import decimal
import json
class DecimalEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, decimal.Decimal):
            return '%.2f' % obj # Display Decimal obj as float
        return json.JSONEncoder.default(self, obj)


class DecimalSerializer(JSONSerializer):
    def end_serialization(self):
        self.options.pop('stream', None)
        self.options.pop('fields', None)
        json.dump(self.objects, self.stream, cls=DecimalEncoder, **self.options)

With this view <

python django serialization
Edit
Report