text: #! /bin/python3
  '''`scifi_wallpaper` module contains methods for setting background image,
  along with the mode. Help: $ python3 scifi_wallpaper_alt1.py'''
  from os import listdir
  from datetime import date
  from subprocess import run
  import click
  
  
  SET_DESK_BG = ['gsettings', 'set', 'org.gnome.desktop.background']  # args 1
  
  @click.group(chain=True)  # group the methods
  def scifi_wallpaper():
      '''scifi_wallpaper group method.'''
  
  @scifi_wallpaper.command()  # scifi-wallpaper group
  def setimg():
      '''Set desktop wallpaper image of the day.'''
      list_imgs = listdir('/home/foo/scripts/scifi_wallpaper/img/')  # img dir
      list_imgs.sort()  # sort filenames d01 thru d31
      img_uri_args = ['picture-uri',
                      'file:///home/foo/scripts/scifi_wallpaper/img/' +
                      list_imgs[date.today().day - 1]]  # args 2
      run(SET_DESK_BG + img_uri_args, check=True)  # run cli args
      print(f'wallpaper img: \x1b[1;34m{list_imgs[date.today().day - 1]}\x1b[0m')
  
  @scifi_wallpaper.command()  # scifi-wallpaper group
  def center():
      '''Centered mode for desktop wallpaper image.'''
      args_center = ['picture-options', 'centered']  # args 2
      run(SET_DESK_BG + args_center, check=True)  # run cli args
  
  @scifi_wallpaper.command()  # scifi-wallpaper group
  def tile():
      '''Tile mode for desktop wallpaper image.'''
      args_tile = ['picture-options', 'wallpaper']  # args 2
      run(SET_DESK_BG + args_tile, check=True)  # run cli args
  
  
  if __name__ == '__main__':
      scifi_wallpaper()  # if standalone
  