Python 单例模式 和工厂模式

class Singleton(object):
    def __new__(cls,*args,**kwargs):
        if not hasattr(cls,‘_inst‘):
            cls._inst=super(Singleton,cls).__new__(cls,*args,**kwargs)
        return cls._inst

class A(Singleton):
    def __init__(self,s):
        self.s = s

a = A(‘test‘)
print dir(a)
b = A(‘test1‘)

print id(a),a.s
print id(b),b.s

class a(object):
   def __init__(self,msg):
      self.msg = msg
   def send(self):
      print (‘send to %s‘%self.msg)
class b(object):
   def __init__(self,msg):
       self.msg=msg
   def send(self):
       print (‘send to vadieo %s‘%self.msg)
   
class ab(a,b):
    def __init__(self,paramater):
    super(ab).__init__
    self.paramater = paramater
    if self.paramater == ‘a‘:
        a.send()
       elif self.paramater == ‘b‘:
           b.send()