python __new__ __init__

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class Student():     def __new__(cls, *args, **kwargs):##创建类的实例         print('__new__')         return object.__new__(cls)##此处返回才会调用__init__     def __init__(self):##初始化类的实例         print('__init__')   class NewInt(int):     def __new__(cls, value):         return int.__new__(cls,abs(value)) #单例横式 class Person():     __isinstance=False     def __new__(cls, *args, **kwargs):         if cls.__isinstance:             return cls.__isinstance         else:             cls.__isinstance = object.__new__(cls)             return cls.__isinstance     def __init__(self):         print('3333') if __name__=='__main__':   stu=Student()   nint=NewInt(-2.45)   print(nint) ##2   p1=Person()   p2 = Person()   print(p1,p2)