(defun picture-mode-exit (&optional nostrip)
"Undo `picture-mode' and return to previous major mode.
-With no argument, strip whitespace from end of every line in Picture buffer;
- otherwise, just return to previous mode.
+With NOSTRIP omitted or nil, strip whitespace from end of every line
+ in Picture buffer; otherwise, just return to previous mode.
+Interactively, NOSTRIP is the prefix argument, and defaults to nil.
Runs `picture-mode-exit-hook' at the end."
(interactive "P")
(if (not (eq major-mode 'picture-mode))