code: def displacements(self):
          
  
          disps = []
          if 'first_atoms' in self._displacement_dataset:
              for disp in self._displacement_dataset['first_atoms']:
                  x = disp['displacement']
                  disps.append([disp['number'], x[0], x[1], x[2]])
          elif 'displacements' in self._displacement_dataset:
              disps = self._displacement_dataset['displacements']
  
          return disps
docs: Return displacements
  
          Returns
          -------
          There are two types of displacement dataset. See the docstring
          of set_displacement_dataset about types 1 and 2 for displacement
          dataset format.
  
          Type-1, List of list
              The internal list has 4 elements such as [32, 0.01, 0.0, 0.0]].
              The first element is the supercell atom index starting with 0.
              The remaining three elements give the displacement in Cartesian
              coordinates.
          Type-2, array_like
              Displacements of all atoms of all supercells in Cartesian
              coordinates.
              shape=(supercells, natom, 3)
              dtype='double'