def describe_features(self, traj):
        n_f = self.partial_transform(traj).shape[1]
        zippy=zip(itertools.repeat("N/A", n_f),
                  itertools.repeat("N/A", n_f),
                  itertools.repeat("N/A", n_f),
                  itertools.repeat(("N/A","N/A","N/A","N/A"), n_f))
        return dict_maker(zippy)