if isinstance(montage, str):  # Predefined layouts
      if montage == '16ch':
          temp = [[0, 0, 1, 0, 0],
                  [0, 1, 1, 1, 0],
                  [0, 1, 1, 1, 0],
                  [1, 1, 1, 1, 1],
                  [0, 1, 1, 1, 0],
                  [0, 0, 1, 0, 0]]
      if montage == '22ch':     # Database BCI competition IV dataset 2a.
          temp = [[0, 0, 0, 1, 0, 0, 0],
                  [0, 1, 1, 1, 1, 1, 0],
                  [1, 1, 1, 1, 1, 1, 1],
                  [0, 1, 1, 1, 1, 1, 0],
                  [0, 0, 1, 1, 1, 0, 0],
                  [0, 0, 0, 1, 0, 0, 0]]
      if montage == '24ch':
          temp = [[0, 1, 0, 0, 1, 0, 0, 1, 0],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [0, 1, 0, 0, 1, 0, 0, 1, 0]]
      if montage == '28ch':
          temp = [[0, 0, 0, 1, 0, 0, 0],
                  [0, 1, 1, 1, 1, 1, 0],
                  [1, 1, 1, 1, 1, 1, 1],
                  [0, 1, 1, 1, 1, 1, 0],
                  [0, 0, 1, 1, 1, 0, 0],
                  [0, 0, 0, 1, 0, 0, 0],
                  [1, 1, 1, 0, 1, 1, 1]]
      if montage == '30ch':
          temp = [[0, 0, 0, 1, 1, 1, 0, 0, 0],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1]]
      if montage == '58ch':
          temp = [[0, 0, 1, 1, 1, 1, 1, 0, 0],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [0, 0, 1, 1, 1, 1, 1, 0, 0],
                  [0, 0, 0, 1, 1, 1, 0, 0, 0]],
      if montage == '60ch':
          temp = [[0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0],
                  [0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0],
                  [0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
                  [0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0],
                  [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
                  [0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0],
                  [0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
                  [0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0]]
      if montage == '64ch':  # order of channels of database GIGA_MI_ME
          temp = [[0, 0, 0, 0, 1, 33, 34, 0, 0, 0, 0],
                  [0, 0, 0, 2, 3, 37, 36, 35, 0, 0, 0],
                  [0, 7, 6, 5, 4, 38, 39, 40, 41, 42, 0],
                  [0, 8, 9, 10, 11, 47, 46, 45, 44, 43, 0],
                  [0, 15, 14, 13, 12, 48, 49, 50, 51, 52, 0],
                  [0, 16, 17, 18, 19, 32, 56, 55, 54, 53, 0],
                  [24, 23, 22, 21, 20, 31, 57, 58, 59, 60, 61],
                  [0, 0, 0, 25, 26, 30, 63, 62, 0, 0, 0],
                  [0, 0, 0, 0, 27, 29, 64, 0, 0, 0, 0],
                  [0, 0, 0, 0, 0, 28, 0, 0, 0, 0, 0]]

                  plot_index = np.where(np.asarray(temp).T == 1)
                  n_rows = np.size(np.asarray(temp), 0)
                  n_cols = np.size(np.asarray(temp), 1)
              else:  # User-defined layouts in the form of a matrix
