简而言之，从python开始，
Where C is a class, the statement
x=C(23)is equivalent to:x = C.__new__(C, 23) if isinstance(x, C): type(x).__init__(x, 23)
From my understanding object.__new__ creates a new, uninitialized instance of the class it receives as its first argument.
Why is there need to be a check with the isinstance(). Isn't it obvious that __new__ will return a object of type C.
如果此测试失败，会发生什么情况？
Since classes are callables, is the call to __new__ is done in the class's __call()__ method
我在这里想念什么吗，请向我澄清一下
