We provide an example optimization of the Branin-Hoo surface with an a priori unknown constraint function c(x), visualized by the shaded region in Figure . The example uses the feasibility-interpolated acquisition strategy (fia-1) with the UCB acquisition function. Two additional arguments to the GPPlanner constructor are required for optimization with unknown constraints. feas strategy indicates the feasibility-aware acquisition type, and the feas param argument indicates the associated parameter. The fia strategies interpolate between the vanilla acquisition function α(x) and the conditional output of the feasibility classifier, P (feasible|x) using the following expression: