LearnerSurvCoxPHCox     R6 Class to construct a Cox proportional
                        hazards survival learner
LearnerSurvGlmnetCox    R6 Class to construct a Glmnet survival learner
                        for Cox regression
LearnerSurvRangerCox    R6 Class to construct a Ranger survival learner
                        for Cox regression
LearnerSurvRpartCox     LearnerSurvRpartCox R6 class
LearnerSurvXgboostAft   R6 Class to construct a Xgboost survival
                        learner for accelerated failure time models
LearnerSurvXgboostCox   R6 Class to construct a Xgboost survival
                        learner for Cox regression
c_index                 c_index
