def maybe_call_closing_deferred(self):

        if self._closing_deferred:
            self._closing_deferred.callback(self)
            self._closing_deferred = None
If the CONF.monkey_patch set as True,
dataset/ETHPy150Open meejah/txtorcon/txtorcon/circuit.py/Circuit.maybe_call_closing_deferred--crossover with--dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/utils.py/monkey_patch