Subclassing int

[G]

Hi,

    I am trying to subclass int to allow a constructor to accept None. I am
trying the following

class INT(int):
    def __init__(self, x):
        if x is  None:
            return None
        else:
            int.__init__(x)

b = INT(x=None)

When i run the previous code i get the following error:
 b = INT(x=None)
TypeError: int() argument must be a string or a number, not 'NoneType'.

Do you guys know why the if statement is not evaluated?

Thanks for your help
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