code: def plot_compare(self, other_plotter):
          
  
          data_orig = self.bs_plot_data()
          data = other_plotter.bs_plot_data()
  
          if len(data_orig['distances']) != len(data['distances']):
              raise ValueError('The two objects are not compatible.')
  
          plt = self.get_plot()
          band_linewidth = 1
          for i in range(other_plotter._nb_bands):
              for d in range(len(data_orig['distances'])):
                  plt.plot(data_orig['distances'][d],
                           [e[i] for e in data['frequency']][d],
                           'r-', linewidth=band_linewidth)
  
          return plt
docs: plot two band structure for comparison. One is in red the other in blue.
          The two band structures need to be defined on the same symmetry lines!
          and the distance between symmetry lines is
          the one of the band structure used to build the PhononBSPlotter
  
          Args:
              another PhononBSPlotter object defined along the same symmetry lines
  
          Returns:
              a matplotlib object with both band structures