Maps ids to feature names.

        Args:
            exp: list of tuples [(id, weight), (id,weight)]

        Returns:
            list of tuples (feature_name, weight)

def map_exp_ids(self, exp):
        """Maps ids to feature names.

        Args:
            exp: list of tuples [(id, weight), (id,weight)]

        Returns:
            list of tuples (feature_name, weight)
        """
        names = self.exp_feature_names
        if self.discretized_feature_names is not None:
            names = self.discretized_feature_names
        return [(names[x[0]], x[1]) for x in exp]