code: def guess_background_color():
      """Returns one of "dark", "light", or "unknown".
  
      This is basically just guessing, but better than always guessing "dark"!
      See also https://stackoverflow.com/questions/2507337/ and
      https://unix.stackexchange.com/questions/245378/
      """
      django_colors = os.getenv("DJANGO_COLORS", "")
      for theme in ("light", "dark"):
          if theme in django_colors.split(";"):
              return theme
      # Guessing based on the $COLORFGBG environment variable
      try:
          fg, *_, bg = os.getenv("COLORFGBG").split(";")
      except Exception:
          pass
      else:
          # 0=black, 7=light-grey, 15=white ; we don't interpret other colors
          if fg in ("7", "15") and bg == "0":
              return "dark"
          elif fg == "0" and bg in ("7", "15"):
              return "light"
      # TODO: Guessing based on the xterm control sequence
      return "unknown"
  
label_desc: Use image node_id 1 for calling a global function with example usage: guess_background_color() and returns: str, theme, str, str