library(mlrMBO)obj.fn = makeMultiObjectiveFunction(    name = "My test function",    fn = function(x1, x2, x3, x4) {        var_1 <- sin(x1 + x2)        var_2 <- cos(x1 - x2)        var_3 <- x1 + x4        var_4 <- x3 + x4 -7        goal_1 = sum(var_1 + var_2 + var_3 + var_4)        goal_2 = var_1 + var_2 - var_3 + var_4        goal_3 = var_1 + var_2 - var_3 + 2*var_4                return(c(goal_1, goal_2, goal_3))            },    n.objectives = 3L,    #define acceptable ranges    par.set = makeParamSet(        makeNumericParam("x1", lower = 20, upper = 40),        makeNumericParam("x2", lower = 30, upper = 45),        makeNumericParam("x3", lower = 10, upper = 20),        makeNumericParam("x4", lower = 10, upper = 50)        #define constraints        , forbidden = expression(x2 >x1 | x3 > x4)    ),        minimize=rep(TRUE,3))#create control gird control=makeMBOControl(propose.points=1, final.method="best.predicted", final.evals=10) control=setMBOControlTermination(control, iters=10) control=setMBOControlInfill(control, crit=makeMBOInfillCritEI())#perform optimizationlrn=makeMBOLearner(control, obj.fun)res = mbo(obj.fun, design = NULL, learner = lrn, control = ctrl, show.info = TRUE)#errorWarning in generateDesign(n.params * 4L, par.set, fun = lhs::maximinLHS) :  generateDesign could only produce 0 points instead of 16!Computing y column(s) for design. Not provided.Error in as.data.frame.OptPathDF(opt.path, include.rest = FALSE) :   No elements where selected (via 'dob' and 'eol')!