i am trying to count how many recent tweets contain 'bitcoin' in their text... i don't think this is right.

tweetcounter.py

#!/usr/bin/python

import json
import urllib.request as r
import urllib.parse as p
from datetime import datetime, timedelta
import pytz

now = pytz.UTC.localize(datetime.utcnow())
delta = timedelta(minutes=3)

def grab(url):
  f = r.urlopen(url)
  doc = f.read().decode()
  f.close()
  return doc

def twitter_search(query):
  return 'http://search.twitter.com/search.json{}'.format(query)

def datetime_recent(dt):
  #now = datetime.utcnow() - timedelta(minutes=3)
  #print('{} is less than {}: {}'.format(now - dt, delta, now - dt < delta))
  return now - dt < delta

def twitter_cmpdate(j):
  # 'created_at': 'Mon, 29 Apr 2013 05:09:26 +0000'
  #print('is {} okay?'.format(j['created_at']))
  dt = datetime.strptime(j['created_at'], '%a, %d %b %Y %H:%M:%S %z')
  return datetime_recent(dt)

def twitter_count_tweets(term):
  query = '?{}'.format(p.urlencode({'q':term}))
  total = 0
  while True:
    j = json.loads(grab(twitter_search(query)))
    r = len([x for x in j['results'] if twitter_cmpdate(x)])
    t = len(j['results'])
    total += r
    print('read {}/{} results on page {}'.format(r,t,j['page']))
    if r==t and 'next_page' in j:
      query = j['next_page']
    else:
      break
  return total

print("{}".format(twitter_count_tweets('bitcoin')))