how to get mongoengine object id in flask program

Question

i am using mongoengine to integrate with flask , i wanted to know how to get document object id every time i try i get File "/var/www/flask_projects/iot_mongo/app.py", line 244, in post return jsonify(user.id) AttributeError: 'BaseQuerySet' object has no attribute 'id'

class Test(Resource):
    def post(self):
        parser = reqparse.RequestParser()
        parser.add_argument('email',required=True, help='email')
        args=parser.parse_args()
        user=AdminUser.objects(email=args['email'])
        return jsonify(user.id)
api.add_resource(Test,'/test')

if __name__ == '__main__':
    app.run(debug=True)