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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def describe_features(self, traj):
 """Return a list of dictionaries describing the LandmarkRMSD features. Parameters traj : mdtraj.Trajectory The trajectory to describe Returns ------- feature_descs : list of dict Dictionary describing each feature with the following information about the atoms participating in each feature - resnames: unique names of residues - atominds: the four atom indicies - resseqs: unique residue sequence ids (not necessarily 0-indexed) - resids: unique residue ids (0-indexed) - featurizer: Alpha Angle - featuregroup: the type of dihedral angle and whether sin or cos has been applied. """

        feature_descs = []
        # fill in the atom indices using just the first frame
        self.partial_transform(traj[0])
        top = traj.topology

        aind_tuples = [self.atom_indices for _ in range(self.sliced_reference_traj.n_frames)]
        zippy = zippy_maker(aind_tuples, top)

        zippy = itertools.product(["LandMarkFeaturizer"], ["RMSD"], [self.sigma], zippy)

        feature_descs.extend(dict_maker(zippy))

        return feature_descs