python 单例模式应用

class Singelton(object):
	__instance=None
	def __init__(self):
		pass
	def __new__(cls,*kwd,**kwargs):
		# if Singelton.__instance is None:
		# 	cls.__instance=object.__new__(cls,*kwd,**kwargs)
		return Singelton.__instance
class a(Singleton):
	def __init__(self,x):
		self.a=x
a1=a(5)
a2=a(6)
print a1.a
print a2.a
print id(a1),id(a2)