Sometimes I find myself in need of this nice operator that I used back in the days when I was programming in .NET, essentially an expression 

>>> expr ?? instead

should return expr when it `is not None` and `instead` otherwise. 

A piece of code that I just wrote, you can see a use case:

    def _sizeof(self, context):
        if self.totalsizeof is not None:
            return self.totalsizeof
            raise SizeofError("cannot calculate size")

With the oprator it would just be

    def _sizeof(self, context):
        return self.totalsizeof ?? raise SizeofError("cannot calculate size")

Arkadiusz Bulski