[hchen19@beeblebrox prototype1]$ python
Python 1.5.2 (#1, Jul  5 2001, 03:02:19)  [GCC 2.96 20000731 (Red Hat Linux 7.1 2 on linux-i386
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
>>> from subject import *  
>>> from plotobserver import *
>>> from data import *
>>> from spreadsheetobserver import *
>>> s=SpreadSheetSubject()
>>> a=PlotObserver(s)
>>> b=SpreadSheetObserver(s)
>>> s.attach(a)
>>> s.attach(b)
>>> s.setState(Data(1,2,6))
plot observer get a new data:  6
spreadsheet observer get a new data:  6
>>>