def assertFlattensImmediately(self, root, target):
        results = []
        it = self.assertFlattensTo(root, target)
        it.addBoth(results.append)
        # Do our best to clean it up if something goes wrong.
        self.addCleanup(it.cancel)
        if not results:
            self.fail("Rendering did not complete immediately.")
        result = results[0]
        if isinstance(result, Failure):
            result.raiseException()
        return results[0]
Return the position.
dataset/ETHPy150Open twisted/twisted/twisted/web/test/_util.py/FlattenTestCase.assertFlattensImmediately--crossover with--dataset/ETHPy150Open babble/babble/include/jython/Lib/mailbox.py/_ProxyFile.tell