api.py

class CardResource(ModelResource):
    ...
    def post_list(self, request, **kwargs):
        deserialized = self.deserialize(request, request.raw_post_data, \
                       format=request.META.get('CONTENT_TYPE', 'application/json'))
        bundle = self.build_bundle(data=dict_strip_unicode_keys(deserialized))
        self.is_valid(bundle, request)

        updated_bundle = self.obj_create(bundle, request=request, user=request.user)

        updated_bundle.obj.get_tracks()
        updated_bundle.obj.get_track_urls()

        return self.create_response(request, self.full_dehydrate(bundle.obj))