$s = @@
def f(x):
    class Once:
        def __init__(self, v):
            self.v = v
            self.extracted = False

        def extract(self):
            assert not self.extracted
            self.extracted = True
            ret = self.v
            self.v = None
            return ret

    return Once(x + 1)

def g(x):
    return x.extract() * 2
@@;

$p = Python::f(Callable<(Int32)->DynamicLinear<Int32>>, $s);
$c = Python::g(Callable<(DynamicLinear<Int32>)->Int32>, $s);

select $c($p(1));