#!/usr/bin/env python
     # encoding: utf-8
     #
     # Copyright (c) 2010 Doug Hellmann.  All rights reserved.
     #
     """Define a new aggregator function.
     """
     #end_pymotw_header
     
     import sqlite3
     import collections
     
     db_filename = 'todo.db'
     
     class Mode(object):
         def __init__(self):
             self.counter = collections.Counter()
         def step(self, value):
             print 'step(%r)' % value
             self.counter[value] += 1
         def finalize(self):
             result, count = self.counter.most_common(1)[0]
             print 'finalize() -> %r (%d times)' % (result, count)
             return result
     
     with sqlite3.connect(db_filename) as conn:
     
         conn.create_aggregate('mode', 1, Mode)
         
         cursor = conn.cursor()
         cursor.execute("select mode(deadline) from task where project = 'pymotw'")
         row = cursor.fetchone()
         print 'mode(deadline) is:', row[0]