@util.synchronized("watcher_do_action")
    @gen.coroutine
    def do_action(self, num):
        # trigger needed action
        if num is 0:
            yield self.manage_processes()
        elif not self.is_stopped():
            # graceful restart
            yield self._reload()
dataset/ETHPy150Open circus-tent/circus/circus/watcher.py/Watcher.do_action/operator `==` -> `is`