def error(message, level="error", exit_code=1, **kwargs):
    kwargs["fg"] = kwargs.get("fg", "red")
    click.secho(u"error: {}".format(message), **kwargs)
    sys.exit(exit_code)
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