presentFeats :: [DAG a (X, Y)] -> [Feature]
presentFeats ds
    =  presentOFeats ds
    ++ presentTFeats (map (fmap snd) ds)
    ++ presentSFeats (map (fmap snd) ds)
presentFeats :: [DAG a (X, Y)] -> [Feature]
presentFeats ds
    =  presentOFeats ds
    ++ presentTFeats (map (fmap snd) ds)
    ++ presentSFeats (map (fmap snd) ds)
presentFeats ds
    =  presentOFeats ds
    ++ presentTFeats (map (fmap snd) ds)
    ++ presentSFeats (map (fmap snd) ds)