_TRAIN_SET_PREEMPH_ARGS
_TRAIN_SET_PREEMPH_ARGS((train_set)[0]), \
_TRAIN_SET_PREEMPH_ARGS((train_set)[1]), \
_TRAIN_SET_PREEMPH_ARGS((train_set)[2]), \
_TRAIN_SET_PREEMPH_ARGS((train_set)[3])