def test_non_callable(self):
        with pytest.raises(TypeError) as excinfo:
            event.event(123)
        excinfo.match(r"Expected string, callable or None as first argument")

        with pytest.raises(TypeError) as excinfo:
            event.event("name")([])
        excinfo.match(r"Callable must be a function \(`def`\)"
                      r" or coroutine function \(`async def`\)")
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