71行出现下面这种情况,请问是什么原因呢?
> f2 <- psm(Surv(time,status) ~ age+sex, data = lung, x=T, y=T, dist='lognormal')
> cal1 <- calibrate(f2, cmethod='KM', method="boot", u=365, m=76, B=228)
Error in UseMethod("calibrate") :
no applicable method for 'calibrate' applied to an object of class "c('psm', 'rms', 'survreg')"