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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _stop_ubridge(self):
 """ Stops uBridge. """


        if self._ubridge_hypervisor and self._ubridge_hypervisor.is_running():
            log.info("Stopping uBridge hypervisor {}:{}".format(self._ubridge_hypervisor.host, self._ubridge_hypervisor.port))
            yield from self._ubridge_hypervisor.stop()
        self._ubridge_hypervisor = None