serializer with custom collection

gistfile1.py

class Doppel2Serializer(serializers.HyperlinkedModelSerializer):
    @property
    def data(self):
        '''If a collection was requested (self.many is True), then we want to
        return the full collection resource, including its own URL. This is
        mostly cribbed from the BaseSerializer definition'''
        if self._data is None:
            obj = self.object

            if self.many:
                self._data = [self.to_native(item) for item in obj]
                view_name = self.opts.model._meta.object_name.lower() + '-list'
                data = {
                    '_href': reverse(view_name,
                                     request=self.context['request']),
                    '_type': 'resource-list',
                    'data': self._data,
                }
                return data
            else:
                self._data = self.to_native(obj)
                return self._data