class Singleton(object):
    def __new__(type):
        if not '_the_instance' in type.__dict__:
            type._the_instance = object.__new__(type)
        return type._the_instance

a=Singleton()
a.toto = 12

b=Singleton()
print b.toto
print id(a),id(b) # the same !!
print a 
print b

## now lets inherit from it:

class Main(Singleton):
    def __init__(self):
    	Singleton.__init__(self)
	## only init if not done already
       	#if not hasattr(self, "x"):
	#	self.x =4

test = Main()
print test
#print test.x 
test.x = 5
print test.x

test2 = Main()
print test2
print test2.x