Get unique followers rate for Twitter

unique_followers_db.py

# -*- coding: utf-8 -*-
"""
Created on Thu Jul  7 18:58:34 2016

@author: paulozullu
"""
from pymongo import MongoClient

''' Creates a connection to MongoDB '''
def connect_mongo(server, db):
    try:
        print "Connecting server %s" %(server)
        client = MongoClient(server, 27017)
        mongo = client[db]
        print "Succesfully connected!"
    except:
        print "Couldn't connect with server %s" %(server)
        exit(1)        

    return mongo
 
def rates():
    
    limits = [10, 20, 50, 80, 94]
    
    for limit in limits:
        w10 = mongo['twitter_follower'].find({})[0:limit]
        
        sum_followers = 0
        unique_followers = []  
        
        for w in w10:
           sum_followers += len(w['followers'])
           
           for f in w['followers']:
               if not f['id'] in unique_followers:
                   unique_followers.append(f['id'])
        
        rate = float(len(unique_followers)) / float(sum_followers)
        
        print "Para %d users temos %d /  %d = %f" % (limit, len(unique_followers), sum_followers, rate)
    
 
# Main Function #
if __name__ == '__main__':
    print "Starting script..."
    mongo = connect_mongo('server_ip', 'db_name')
    rates()