code: def plot_brillouin(self):
          
  
          # get labels and lines
          labels = {}
          for k in self._bs.kpoints:
              if k.label:
                  labels[k.label] = k.frac_coords
  
          lines = []
          for b in self._bs.branches:
              lines.append([self._bs.kpoints[b['start_index']].frac_coords,
                            self._bs.kpoints[b['end_index']].frac_coords])
  
          plot_brillouin_zone(self._bs.lattice_rec, lines=lines, labels=labels)
docs: plot the Brillouin zone