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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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