If there are hidden CPOs (e.g. if a learner has CPOs, but is then wrapped by a
this function can not retrieve these CPOs, but it will emit a warning if
The retrieved CPOs will have the hyperparameter set according to the hyperparameter settings of the Learner.
This function is complementary to
getLearnerCPO(learner, warn.buried = TRUE)
CPO]. The (possibly composite) CPO found attached to