using observer pattern to perform model notification to subscribers

Thismight be a little long question but i try to keep it as small as possible and try to put it in the best way i can.

I have reading about design patterns and found observer pattern very intresting. i searched for its practical application and found various answers here. one of those answer was:

Whenever a question is posted, all the subscribers following the topics of similar interest are notified.

i tried to model this system in python as below:

using Mongoengine ORM to model a User and define a function notify for the User class which can be used to notify a user:

from mongoengine import *

connect('tumblelog')


# User model
class User(Document):
        email = StringField()
        first_name = StringField()
        last_name = StringField()
        topic_subscribed = StringField()

        def notify(self):
                print "email sent to user :{} {} {}".format(self.first_name, self.last_name, self.email)
                print "user was subsacribed to: {}".format(self.topic_subscribed)






# simulate publishing of an article of a particular topic
while True:
        x = raw_input(">>>")
        print "question of {} topic published".format(x)

        # How to notify all users that are subscribed to the topic ?????
        # naive way :
        # def some_aynchronous_function():
        #       1) find all users from db that are subscribed to the topic
        #       2) notify each user by looping through all of them          

I know the trivial way it can be done but can I do something better by using observer pattern here?

NOTE: I am not trying to fit the problem to the design pattern as it is usually frowned upon. I am just trying to implement it for *learning purpose. I have tried searching for some implementations but unsuccessful so far

MY QUESTION : I presented the way I know I could have approached the problem(pseudocode above) but is there anything that can be done better using an observer pattern here?