If image not found, set clipboard to "img not found"

Hi,
Currently Im using...
reg.click(Image) (if image doesn't appear within default wait time stop script)
and
reg.wait(Image, 9) (if image doesn't appear within 9 seconds stop script)
I remember the default wait was about 3 seconds

How can I tell sikuli that
if image doesn't appear set clipboard as "image not found" and only then stop script, (it's necessary to stop script after clipboard change)

I have used...

try:
    reg.click(Image)
except
    App.setClipboard("image not found")

which is the best way to achieve this? thanks advanced.