def METHOD_NAME(self):
    """Test the creation of a new CustomFactor"""
    def error_func(this: CustomFactor, v: gtsam.Values,
                   H: List[np.ndarray]):
        """Minimal error function stub"""
        return np.array([1, 0, 0])
    noise_model = gtsam.noiseModel.Unit.Create(3)
    cf = CustomFactor(noise_model, [0], error_func)