code: def partial_transform(self, traj):
          
          seq_id = [k for k, v in self.all_sequences.items()
                    if v == traj.top.to_fasta(chain=0)][0]
          return self.feat_dict[seq_id].partial_transform(traj)
docs: Featurize an MD trajectory into a vector space derived from
          residue-residue distances
  
          Parameters
          ----------
          traj : mdtraj.Trajectory
              A molecular dynamics trajectory to featurize.
  
          Returns
          -------
          features : np.ndarray, dtype=float, shape=(n_samples, n_features)
              A featurized trajectory is a 2D array of shape
              `(length_of_trajectory x n_features)` where each `features[i]`
              vector is computed by applying the featurization function
              to the `i`th snapshot of the input trajectory.
  
          See Also
          --------
          transform : simultaneously featurize a collection of MD trajectories
  
          Warning
          -------
          Only works for chain 0 for now.