docs: def handle_exit_code(d, code):
      """Sample function showing how to interpret the dialog exit codes.
  
      This function is not used after every call to dialog in this demo
      for two reasons:
  
         1. For some boxes, unfortunately, dialog returns the code for
            ERROR when the user presses ESC (instead of the one chosen
            for ESC). As these boxes only have an OK button, and an
            exception is raised and correctly handled here in case of
            real dialog errors, there is no point in testing the dialog
            exit status (it can't be CANCEL as there is no CANCEL
            button; it can't be ESC as unfortunately, the dialog makes
            it appear as an error; it can't be ERROR as this is handled
            in dialog.py to raise an exception; therefore, it *is* OK).
  
         2. To not clutter simple code with things that are
            demonstrated elsewhere.
  
      """
      # d is supposed to be a Dialog instance
      if code in (d.DIALOG_CANCEL, d.DIALOG_ESC):
          if code == d.DIALOG_CANCEL:
              msg = "You chose cancel in the last dialog box. Do you want to " \
                    "exit this demo?"
          else:
              msg = "You pressed ESC in the last dialog box. Do you want to " \
                    "exit this demo?"
          # "No" or "ESC" will bring the user back to the demo.
          # DIALOG_ERROR is propagated as an exception and caught in main().
          # So we only need to handle OK here.
          if d.yesno(msg) == d.DIALOG_OK:
              sys.exit(0)
          return 0
      else:
          return 1