[Python] __new__ function behaves differently after overriding it with setattr

I have the following:

class A:
def __init__(self, x):
self.x = x

A(5) # Works fine
x = A.__new__ # Save the function
A.__new__ = lambda y: y # Temporarily override it
A.__new__ = x # Restore the function
A(5) # RAISES AN EXCEPTION!


The last call raises an exception:

TypeError: object.__new__() takes exactly one argument (the type to instantiate)


What happens here?

I'll add that x, prior to the override, was being called just fine as a __new__ function. But after the override (and the restore), it lost its ability to accept any number of arguments (*args, **kwargs).

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