code: def get_elements_between_bands(self, band_i, band_j):
          
          if band_i < 1 or band_i > self.nb_bands or band_j < 1 or band_j > self.nb_bands:
              raise ValueError("Band index out of bounds")
  
          return self.data[:, band_i - 1, band_j - 1, :]
docs: Method returning a numpy array with elements
  
          [cdum_x_real, cdum_x_imag, cdum_y_real, cdum_y_imag, cdum_z_real, cdum_z_imag]
  
          between bands band_i and band_j (vasp 1-based indexing) for all kpoints.
  
          Args:
              band_i (Integer): Index of band i
              band_j (Integer): Index of band j
  
          Returns:
              a numpy list of elements for each kpoint