def sub_split_values(self, sub):
        """ Substitutes the splits with other values into the split_map """
        for i, arr in enumerate(self.splits):
            self.split_map[i] = [sub.get(x, x) for x in arr]
        for split in self.surrogates:
            split.sub_split_values(sub)
Substitutes the splits with other values into the split_map