docs: def parts():
      '''
      Returns the dictionary with the part as key and the contained book as indices.
      '''
      parts = {
          'Canon': [ _ for _  in range(1, 5) ],
          'Apostle': [ 5 ],
          'Paul': [ _ for _ in range(6, 19) ],
          'General': [ _ for _ in range(19, 26) ],
          'Apocalypse': [ 27 ]
      }
      return parts