code: def partial_transform(self, traj):
          
          if self.soft_min:
              distances, _ = md.compute_contacts(traj, self.contacts,
                                                 self.scheme, self.ignore_nonprotein,
                                                 soft_min=self.soft_min,
                                                 soft_min_beta=self.soft_min_beta,
                                                 periodic=self.periodic)
          else:
              distances, _ = md.compute_contacts(traj, self.contacts,
                                                 self.scheme, self.ignore_nonprotein,
                                                 periodic=self.periodic)
          return self._transform(distances)
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