def test_get_root_on_create(self):
        root_on_create_val = Instance.get_root_on_create(
            'redis')
        self.assertFalse(root_on_create_val)
def _cost_gp_withGradients(self,x):
        """
        Predicts the time cost and its gradient of evaluating the function at x.
        """
        m, _, dmdx, _= self.cost_model.predict_withGradients(x)
        return np.exp(m), np.exp(m)*dmdx