def exists(self):
        try:
            self.first()
        except NotFoundError:
            return False
        return True
Utility method to substitute variables in strings.
dataset/ETHPy150Open beetbox/beets/beets/util/confit.py/ConfigView.exists--crossover with--dataset/ETHPy150Open ucb-sts/sts/sts/entities/controllers.py/ControllerConfig._expand_vars